United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued December 10, 2020 Decided April 16, 2021

No. 20-5026

GENUS MEDICAL TECHNOLOGIES LLC,

APPELLEE

v.

UNITED STATES FOOD AND DRUG ADMINISTRATION,

APPELLANT

Appeal from the United States District Court

for the District of Columbia

(No. 1:19-cv-00544)

Daniel Winik, Attorney, U.S. Department of Justice, 

argued the cause for appellant. With him on the briefs were 

Jeffrey Bossert Clark, Acting Assistant Attorney General, Scott 

R. McIntosh, Attorney, Robert P. Charrow, General Counsel, 

U.S. Department of Health and Human Services, AnnaMarie 

Kempic, Deputy Chief Counsel for Litigation.

Noam B. Fischman was on the brief for amicus curiae 

Bracco Diagnostics Inc. in support of appellant.

James A. Boiani was on the brief for amicus curiae Giskit 

B.V. in support of appellant.
2

Douglas B. Farquhar argued the cause and filed the brief 

for appellee.

Before: HENDERSON, PILLARD and KATSAS, Circuit 

Judges.

Opinion for the Court filed by Circuit Judge HENDERSON.

Opinion concurring in the judgment filed by Circuit Judge 

PILLARD.

KAREN LECRAFT HENDERSON, Circuit Judge: The Federal 

Food, Drug, and Cosmetic Act (FDCA or Act), 21 U.S.C. 

§§ 301 et seq., sets forth separate and detailed regimes for the 

regulation of medical products classified, inter alia, as drugs or

devices. The question before us is whether the U.S. Food and 

Drug Administration (FDA) enjoys discretion to classify as a 

“drug” a product that meets the statutory definition of a 

“device.” The FDA claims that, if a medical product satisfies 

the statutory definitions of both a “drug” and a “device,” the 

Act’s overlapping definitions grant by implication the FDA 

broad discretion to regulate the product under either regime.

Since 2017 the FDA has exercised its claimed discretion to 

classify Genus Medical Technologies’ (Genus) “Vanilla SilQ” 

line of diagnostic contrast agents as drugs, notwithstanding the 

FDA’s recognition that the products “appear” to satisfy the 

statutory definition for devices. Genus subsequently filed suit, 

challenging the FDA’s classification decision as inconsistent 

with the Administrative Procedure Act (APA), 5 U.S.C. 

§ 706(2), and the FDCA. Finding that the FDCA

unambiguously foreclosesthe FDA’s interpretation, the district 

court granted summary judgment in Genus’s favor and vacated 

the FDA decision to classify Genus’s products as drugs. We 

agree with the district court that the text, statutory structure and 

legislative history of the Act make plain that the Congress did 
3

not grant the FDA such sweeping discretion. Accordingly, we

affirm the district court’s grant of summary judgment. 

I. BACKGROUND

A. Statutory & Regulatory Framework

The FDCA grants the FDA the authority to regulate certain 

categories of medical products, including drugs, devices,

biologics and dietary supplements. Relevant here are the 

statutory definitions for “drug” and “device.” The Act, in 

relevant part, defines “drugs” to include: 

articles intended for use in the diagnosis, cure, 

mitigation, treatment, or prevention of disease 

in man or other animals . . . .

21 U.S.C. § 321(g)(1)(B). “Devices” are defined to include:

an instrument, apparatus, implement, machine, 

contrivance, implant, in vitro reagent, or other 

similar or related article, including any 

component, part, or accessory, which is . . . 

intended for use in the diagnosis of disease or 

other conditions, or in the cure, mitigation, 

treatment, or prevention of disease, in man or 

other animals, . . . and which does not achieve 

its primary intended purposes through chemical 

action within or on the body of man or other 

animals and which is not dependent upon being 

metabolized for the achievement of its primary 

intended purposes.
4

Id. § 321(h)(1).

1 Because the two definitions share a common

“intended-use clause”—that is, both definitions include articles 

intended for use in the diagnosis, cure, mitigation, treatment or 

prevention of disease—and because the drug definition 

features no other relevant limitations, it is apparent that any 

product that satisfies the “device” definition also satisfies the 

definition of a “drug.” The converse, however, is not true. 

Because a device must be “an instrument, apparatus, 

implement, machine, contrivance, implant, in vitro reagent, or 

other similar or related article,” and further, because it may 

neither “achieve its primary intended purposes through 

chemical action within or on the body of man” nor be 

“dependent upon being metabolized for the achievement of its 

primary intended purposes,”2 the set of products that satisfy the 

device definition is necessarily encompassed by, but narrower

than, the set of products that satisfy the drug definition.

Drugs and devices are subject to distinct regulatory 

regimes. To begin, separate divisions of the FDA are primarily 

responsible for each product category. Whereas drugs are 

1 At the time of the FDA’s decision, the device definition was 

located at 21 U.S.C. § 321(h). The Congress later relocated the 

amendment to 21 U.S.C. § 321(h)(1). See Safeguarding 

Therapeutics Act, Pub. L. No. 116-304, § 2(b), 134 Stat. 4915, 4916 

(2011) (codified at 21 U.S.C. § 321(h)(1)).

2 Although FDA guidance refers to these “primary intended 

purpose[]” limitations as the device definition’s “exclusionary 

clause” or exclusionary clauses, Classification of Products as Drugs 

and Devices & Additional Product Classification Issues: Guidance 

for Industry and FDA Staff, U.S. Dep’t of Health and Human Servs., 

FDA, 6 & n.11 (Sept. 2017), 

https://www.fda.gov/media/80384/download, we refer to them as the 

“mode-of-action clauses” in order to distinguish them from the 

“instrument clause,” which also has the effect of “excluding” certain 

products that would otherwise satisfy the device definition. See 

supra n.1.
5

generally regulated by the FDA’s Center for Drug Evaluation 

and Research, devices are within the purview of the FDA’s 

Center for Devices and Radiological Health. 

The FDA holds new drugs to a high standard of pre-market 

review and approval. To market a new prescription drug, the 

sponsor (typically the manufacturer) must submit a new-drug 

application and demonstrate through clinical trials that the drug 

is safe and effective for its proposed use. 21 U.S.C. § 355(a)–

(b). Sponsors may, however, be able to take advantage of an 

abbreviated new-drug application if their drug is sufficiently 

similar to drugs that the FDA has previously approved. Id.

§ 355(j). 

The FDA’s pre-market review of devices is more varied.

Devices are assessed by the FDA and, with the assistance of 

expert “classification panels,” classified into one of three 

categories based on the risks they pose. Id. § 360c. First are 

Class I devices, which are “subject only to minimal regulation

by ‘general controls’” because they “present no unreasonable 

risk of illness or injury . . . .” Medtronic, Inc. v. Lohr, 518 U.S. 

470, 476–77 (1996) (quoting 21 U.S.C. § 360c(a)(1)(A)). 

Class II devices include “[d]evices that are potentially more 

harmful” and, “although they may be marketed without 

advance approval, manufacturers of such devices must comply 

with federal performance regulations known as ‘special 

controls.’” Id. at 477 (quoting 21 U.S.C. § 360c(a)(1)(B)). 

Finally, devices that, inter alia, “‘presen[t] a potential 

unreasonable risk of illness or injury,’ or which are ‘purported 

or represented to be for a use in supporting or sustaining human 

life or for a use which is of substantial importance in preventing 

impairment of human health’” are generally classified as Class 

III and, like drugs, subject to pre-market approval. Id.

(alteration in original) (quoting 21 U.S.C. § 360c(a)(1)(C)); 21 

U.S.C. § 360e. To introduce a new Class III device into the 
6

market, the sponsor must provide the FDA with “detailed 

information regarding the safety and efficacy” of the device 

and the FDA must have “‘reasonable assurance’ that the device 

is both safe and effective.” Medtronic, 518 U.S. at 477

(quoting 21 U.S.C. § 360e(d)(2)).

The regulatory differences do not end at the product 

approval stage. Throughout the lifecycle of a medical product, 

its treatment by the FDA depends upon its classification as 

either a drug or a device. The FDCA sets forth separate rules

for, inter alia, annual manufacturer registration, compare 21 

U.S.C. § 360(b)(1) (registration requirements for drug 

manufacturers), with id. § 360(b)(2) (registration requirements 

for device manufacturers); routine manufacturer inspections, 

compare 21 U.S.C. § 360(h)(3) (risk-based inspection 

schedules for drug manufacturers), with id. § 360(h)(2) (riskbased inspection schedules for device manufacturers); routine 

product reporting, see id. § 356i (reporting of marketing status 

for drugs only); and adverse-event reporting, compare id. 

§ 355b (reporting of adverse drug events), with id. § 360i 

(records and reports on devices, including reporting of adverse 

device events). 

The result is that, on average, it is more costly for a sponsor 

to develop and market a product as a drug than it would be to 

develop and market an otherwise identical product as a device. 

Genus maintains that its cost would be approximately $60,000 

to seek device clearance for Vanilla SilQ—the product line in 

question here. Genus Med. Techs., LLC v. FDA, 427 F. Supp. 

3d 74, 78 (D.D.C. 2019). If, however, the same product line

were classified as drugs, Genus estimates that it would cost 

them more than $500,000 to obtain pre-market approval in 

addition to a recurring cost of more than $186,000 per year to 

continue marketing their products as drugs. Id. 
7

Fortunately for sponsors, the FDCA contemplates at least 

a limited role for sponsor input in the course of the product 

classification process. Specifically, if the classification of a 

product is unclear, a product sponsor may file a request for

designation (RFD) to obtain a formal, binding determination 

from the FDA as to the “classification of the product . . . or . . . 

the component of the [FDA] that will regulate the product.” 21 

U.S.C. § 360bbb-2(a). A sponsor submits its RFD—including 

a recommended classification—to the FDA’s Office of 

Combination Products (OCP) and the OCP must respond 

thereto no later than 60 days after the RFD’s filing. Id.

§ 360bbb-2(b). If the OCP fails to respond, the sponsor’s 

recommended classification becomes final. Id. § 360bbb-2(c). 

A classification made through the RFD process cannot be 

changed “except with the written consent of the [sponsor], or 

for public health reasons based on scientific evidence.” Id.

§ 360bbb-2(b)–(c).

B. Factual and Procedural History

Genus has manufactured its Vanilla SilQ product line 

since 2015. Compl. ¶ 25. Vanilla SilQ belongs to a category 

of products known as contrast agents. Contrast agents are used 

in medical imaging to improve the visualization of tissues, 

organs and physiological processes. According to Genus, 

Vanilla SilQ is an oral solution used in combination with X-ray 

examinations or other radiologic procedures to enhance the 

visualization of the gastrointestinal tract for diagnostic 

purposes. The product’s key ingredient is an inert metal salt 

known as barium sulfate. When swallowed, the barium sulfate 

coats the inside of the individual’s gastrointestinal tract and 

facilitates the absorption of X-rays. Subsequently, the X-ray 

examination will appear lighter for areas coated with barium 

sulfate and darker for the surrounding tissues that are not 

coated. Although some contrast agents cannot be classified as 
8

devices because they achieve their primary intended purpose

through metabolization or chemical action within or on the 

body of man, the FDA agrees that Genus’s Vanilla SilQ 

product line “appear[s] to meet the definition of ‘device’”

insofar as it does not achieve its primary intended purposes 

through either of the excluded modes.3 Appellant’s Br. 12–13. 

Genus avers “that before and after it started producing 

Vanilla SilQ, it sought FDA clearance to distribute its 

products” as either devices or grandfathered drugs (which, 

unlike new drugs, do not require pre-market approval). Genus, 

427 F. Supp. 3d at 79. In June 2016, however, the FDA 

conducted a three-day inspection of Genus’s distribution 

facility. Id. The result of the inspection was a warning letter, 

issued on May 2, 2017, notifying Genus that its products 

constituted “drugs” within the meaning of the FDCA. Id. 

Genus, responding to the FDA in a letter dated May 19, 2017, 

asserted that its products are devices and that the FDA could 

not regulate them as drugs because they do not “achieve [their] 

3 We note that it is not immediately obvious to us how a contrast 

agent satisfies the device definition’s requirement that the regulated 

product be “an instrument, apparatus, implement, machine, 

contrivance, implant, in vitro reagent, or other similar or related 

article, including any component, part, or accessory . . . .” 21 U.S.C. 

§ 321(h)(1). Nor is it altogether settled that Vanilla SilQ satisfies the 

device definition’s mode-of-action clauses. Compare, e.g., Amicus 

Bracco Br. 5–6 (arguing that Vanilla SilQ may not be regulated as a 

device because it achieves its primary intended purpose through 

chemical action), with Appellee’s Br. 52 (arguing that Vanilla SilQ 

does not achieve its primary intended purpose through chemical 

action). Because neither question is part of the administrative 

decision now under review—the FDA found only that Genus’s 

products “appear to meet” the device definition, see Joint Appendix

(J.A.) 122, 152, and both parties continue to agree that they do—we 

reserve the question whether Vanilla SilQ satisfies the device

definition’s instrument and mode-of-action clauses.
9

primary intended purposes through chemical action within or 

on the body” or through “metaboliz[ation].” J.A. 157–61

(quoting 21 U.S.C. § 321(h)(1)). On September 6, 2018, the 

FDA responded that, “[a]lthough [the Vanilla SilQ products] 

appear to meet the definition of ‘device’ . . . they also meet the 

definition of ‘drug’ [under the FDCA] because they are articles 

intended for use in the diagnosis of disease.” Id. at 152. The 

FDA stated that “[w]hile [it] generally regulates products that 

meet the definition of a device under the device authorities, 

there are certain exceptions” and “[b]ecause not all contrast 

agents meet the definition of a device, but all of them do meet 

the definition of a drug, [it] has for many years regulated these 

products as drugs in order to regulate them consistently under 

the same authority . . . .” Id.

Having failed to convince the FDA through its 

correspondence, Genus next submitted an RFD, in which it 

formally requested that the OCP classify its Vanilla SilQ 

products as devices under the FDCA. Genus, 427 F. Supp. 3d 

at 79–80. The OCP responded with an official Designation 

Letter in which it echoed the FDA’s previous reasoning that, 

although the Vanilla SilQ products appeared to meet the 

definitions for both a device and a drug, it was nonetheless 

appropriate to regulate uniformly all contrast agents as drugs. 

Id. at 80. 

On February 28, 2019 Genus filed suit in district court. In 

addition to certain claims not relevant here, Genus claimed that 

the FDA’s decision to regulate Vanilla SilQ as a drug rather 

than as a device was arbitrary and capricious and in excess of 

statutory authority under the FDCA and the APA. In a decision 

filed December 6, 2019, the district court granted summary 

judgment to Genus, concluding that the plain language of the 

FDCA unambiguously requires that “a product that meets the 

device definition must be regulated as such” and that the court 
10

must therefore “end[] its analysis at Chevron step one.” Genus, 

427 F. Supp. 3d at 84. The district court vacated the FDA’s 

classification of Vanilla SilQ as a drug and remanded the 

matter to the FDA for further proceedings. Id. at 87. 

II. ANALYSIS

Our review of a summary judgment grant is de novo, 

affirming only if “there is no genuine issue as to any material 

fact [and] the moving party is entitled to judgment as a matter 

of law.” Mylan Labs., Inc. v. Thompson, 389 F.3d 1272, 1278–

79 (D.C. Cir. 2004) (alteration in original) (quoting Trans 

Union LLC v. Fed. Trade Comm’n, 295 F.3d 42, 48 (D.C. Cir. 

2002)). In a case like this one, in which the district court 

reviewed an agency action under the APA, “[w]e review the 

administrative record and give no particular deference to the 

District Court’s views.” Eagle Pharms., Inc. v. Azar, 952 F.3d 

323, 329–30 (D.C. Cir. 2020) (quoting Am. Bankers Ass’n v. 

Nat’l Credit Union Admin., 934 F.3d 649, 662 (D.C. Cir. 

2019)). We review the FDA decision to classify Genus’s 

products, then, under the familiar standards of the 

Administrative Procedure Act, which require that we uphold 

the FDA decision unless it is “arbitrary, capricious, an abuse of 

discretion, or otherwise not in accordance with law” or “in 

excess of statutory jurisdiction, authority, or limitations . . . .”

5 U.S.C. § 706(2). We defer to the FDA’s interpretation of the 

FDCA “so long as the Congress has not unambiguously 

forbidden it and it is otherwise permissible.” Cal. Metro 

Mobile Commc’ns, Inc. v. FCC, 365 F.3d 38, 43 (D.C. Cir. 

2004) (citing Chevron U.S.A., Inc. v. Nat. Res. Def. Council, 

Inc., 467 U.S. 837, 842–43 (1984)); see also Teva Pharms. 

USA, Inc. v. Sebelius, 595 F.3d 1303, 1315 (D.C. Cir. 2010) 

(applying Chevron framework to FDA interpretations of 

FDCA contained in letter rulings); Mylan Labs., 389 F.3d at 

1279–80 (same). Our task requires that “[w]e examine the 
11

statute’s text, structure, purpose, and legislative history to 

determine if the Congress has expressed its intent 

unambiguously.” Eagle Pharms., 952 F.3d at 330 (alteration 

omitted) (quoting U.S. Sugar Corp. v. EPA, 830 F.3d 579, 605 

(D.C. Cir. 2016) (per curiam)).

A. FDCA’s Text

The question before us is a purely legal one: whether the 

FDCA grants the FDA discretion to classify as a “drug” a 

product that satisfies the statutory definitions of both a “drug” 

and a “device.” In answering the question, “[w]e begin ‘where 

all such inquiries must begin: with the language of the statute 

itself.’” Caraco Pharm. Labs., Ltd. v. Novo Nordisk A/S, 566 

U.S. 399, 412 (2012) (quoting United States v. Ron Pair 

Enters., Inc., 489 U.S. 235, 241 (1989)). We are mindful, 

however, that if the text alone is insufficient to end the inquiry, 

we may turn to other “customary statutory interpretation tools,” 

including “‘structure, purpose, and legislative history.’” Cal. 

Metro Mobile, 365 F.3d at 44–45 (quoting Consumer Elecs. 

Ass’n v. FCC, 347 F.3d 291, 297 (D.C. Cir. 2003)); see also 

Chevron, 467 U.S. at 843 n.9 (“If a court, employing traditional 

tools of statutory construction, ascertains that Congress had an 

intention on the precise question at issue, that intention is the 

law and must be given effect.”) (emphasis added). We 

conclude that the FDCA’s text unambiguously forecloses the 

FDA’s interpretation.

The parties’ dispute is purely legal. Genus contends that 

when a product satisfies both the drug and device definitions of 

the FDCA, the product is a device. Conversely, the FDA 

argues that it can choose whether to treat products that satisfy 

both definitions as drugs or devices. Because the FDA’s legal 

theory did not require it to do so, it made no factual findings 

about whether the Vanilla SilQ products satisfied the particular 
12

requirements of the FDCA’s device definition. Instead, it 

found only that the products fell within the drug definition and 

remarked that they “appear” to also satisfy the device 

definition. 

Beginning with the statute’s text, the FDA argues that, 

because it is possible for a product to simultaneously satisfy the 

linguistic demands of both the drug and device definitions, the 

Congress must have granted the FDA discretion in such 

instance to choose a classification. Simply put, any product 

meeting the device definition may be classified as a device, any 

product meeting the drug definition may be classified as a drug 

and, according to the FDA’s reading, any product meeting both 

definitions may be classified as either. To the extent the FDCA 

is silent on how to treat products that meet both definitions, the 

FDA argues that we should read it as a sign of statutory 

ambiguity and defer to the FDA’s purportedly reasonable 

interpretation. 

Whereas the FDA draws our attention to the definitional 

overlap, Genus urges us to focus on the elements of the device 

definition that set it apart, including, most prominently, its 

mode-of-action clauses. Genus argues that, because the drug 

and device definitions are broadly similar except for the device 

definition’s mode-of-action clauses—excluding products that 

achieve their primary intended purposes through “chemical 

action within or on the body of man” or “metaboliz[ation],” 21 

U.S.C. § 321(h)(1)—products that do not achieve their primary 

intended purposes through either excluded mode (and that 

otherwise satisfy both definitions) must be regulated as devices 

and devices alone. According to Genus, any other 

interpretation would “effectively read[] the Mode of Action 

Clause[s] out of the statute.” Appellee’s Br. 23. 
13

Genus also urges us to rely on two traditional canons of 

statutory construction. First, the “old and familiar rule” that 

“the specific governs the general.” RadLAX Gateway Hotel, 

LLC v. Amalgamated Bank, 566 U.S. 639, 645–46 (2012) 

(quoting United States v. Chase, 135 U.S. 255, 260 (1890); 

Morales v. Trans World Airlines, Inc., 504 U.S. 374, 384 

(1992)). And second (and relatedly), the basic interpretive 

canon that a “statute should be construed [to give effect] to all 

its provisions, so that no part will be inoperative or superfluous, 

void or insignificant.” Corley v. United States, 556 U.S. 303, 

314 (2009) (quoting Hibbs v. Winn, 542 U.S. 88, 101 (2004)). 

Applying these canons, Genus argues that the FDA’s 

interpretation would render the device definition’s mode-ofaction clauses inoperative and allow the device definition to be 

“swallowed by the more general drug definition.” Appellee’s

Br. 30–31 (quoting Genus, 427 F. Supp. 3d at 83). 

Although we are unpersuaded that the FDA’s 

interpretation would render the mode-of-action clauses 

completely inoperative—under the FDA’s theory, the modeof-action clauses would still be necessary for differentiating 

products that may be regulated as devices from those that may 

not—we nonetheless agree with Genus that this is a case where 

the specific must govern the general. The FDA does not 

dispute that the FDCA’s definition of a “device” is drawn more 

narrowly than its definition of a “drug.” Indeed, as we 

discussed above, supra Section I.A, the set of products that 

satisfy the device definition is necessarily encompassed by, but 

narrower than, the set of products that satisfy the drug 

definition.4 Moreover, the general-specific canon is 

4 The concurring opinion contends that recognizing complete 

overlap in the definitions would render the instrument clause 

surplusage. Concurring Op. 7–8. But the instrument clause, like the 

mode-of-action clauses, necessarily restricts which medical products 

are devices. It does clear work in determining which medical 
14

particularly appropriate where, as here, the provisions at issue 

are “interrelated and closely positioned” as “parts of the same 

statutory scheme.” RadLAX Gateway Hotel, 566 U.S. at 645

(alteration adopted) (quoting HCSC-Laundry v. United States, 

450 U.S. 1, 6 (1981) (per curiam)). Thus, the device 

definition’s instrument and mode-of-action clauses make it a 

classic candidate for application of the canon that the specific 

governs the general, and to the extent the drug and device

definitions conflict, it is the narrower definition—the device 

definition—to which we must give effect. See D. Ginsberg & 

Sons, Inc. v. Popkin, 285 U.S. 204, 208 (1932) (“Specific terms 

prevail over the general in the same or another statute which 

otherwise might be controlling.”).

The only question, then, is whether the two definitions are 

truly in conflict. The FDA claims they are not. More 

specifically, according to the FDA, the general-specific canon 

is inapplicable here because it is “most frequently applied to 

statutes in which a general permission or prohibition is 

contradicted by a specific prohibition or permission” or where 

“a general authorization and a more limited, specific 

authorization exist side-by-side.” RadLAX Gateway Hotel, 566 

U.S. at 645. The FDA argues that there is no such contradiction 

here because the provisions in question are definitions as 

opposed to authorizations or prohibitions and both definitions 

can be given simultaneous effect. There is “no reason,” 

according to the FDA’s opening brief, that “the statute must be 

read so that a given product qualifies as either a ‘drug’ or a 

‘device,’ but not both.” Appellant’s Br. 24 (emphasis in 

original). 

On this point the FDA is mistaken. In theory, it may be 

possible for a product to satisfy both definitions at once. What 

products, from among those that satisfy the broader drug definition, 

also satisfy the narrower device definition. 
15

the FDA omits, however, is that the FDCA’s statutory 

definitions are meaningful only insofar as they carry concrete 

regulatory consequences. As discussed, the FDCA elaborates 

distinct regulatory regimes for drugs and devices. And each 

scheme is mandatory: The FDCA prohibits the sale of “any

new drug” not approved under the regime for drug approvals. 

21 U.S.C. § 355(a) (emphasis added). Similarly, all new Class 

III devices are “required” to satisfy the pre-market review 

regime for devices, id. § 360e(a), and Class I and Class II 

devices must meet other distinct requirements, see id. § 360c. 

Nor can the Secretary circumvent these requirements. Id.

§ 355(c)(1) (Secretary “shall” either approve new-drug 

application pursuant to drug regime or deny application); 

§ 360c(b)(1) (Secretary “shall” classify “all” new devices 

intended for human use into three device classes). In short, it 

is not textually possible to say that an item is a drug (or device) 

but need not be regulated as such. And no one suggests that 

the FDCA requires products meeting both definitions to be 

regulated both as drugs and devices, which would create a 

breathtaking example of statutory redundancy. The statute, 

then, is clear: a product may be regulated as a drug or a device, 

but not both, and while a single product may simultaneously 

satisfy the linguistic elements of two definitions, it is not 

possible for the FDA to give simultaneous effect to both. Thus,

this is precisely the sort of setting in which we must give effect 

to the specific over the general. To do otherwise would be in 

violation of the “settled” principle that “[h]owever inclusive 

may be the general language of a statute, it will not be held to 

apply to a matter specifically dealt with in another part of the 

same enactment.” Fourco Glass Co. v. Transmirra Prods. 

Corp., 353 U.S. 222, 228 (1957) (quoting Clifford F. MacEvoy 

Co. v. U.S. ex rel. Calvin Tomkins Co., 322 U.S. 102, 107 

(1944)).
16

Before proceeding to the parties’ structural claims, we 

briefly dispatch with the FDA’s argument that we should be 

guided by a 1990 amendment to the FDCA’s drug definition. 

Specifically, the FDA argues that interpreting the drug and 

device definitions as mutually exclusive would be to 

“effectively read[] back into the statute” an old version of the 

drug definition the Congress affirmatively abandoned when it 

adopted the Safe Medical Devices Act of 1990 (SMDA), Pub. 

L. No. 101-629, 104 Stat. 4511. Appellant’s Br. 21–22. Before

1990, the FDCA definition of a drug specifically excluded 

“devices or their components, parts, or accessories.” FDCA, 

Pub. L. No. 75-717, § 201(g), 52 Stat. 1040, 1041 (1938)

(codified as amended at 21 U.S.C. § 321(g)(1)). The 1990 

SMDA struck this exclusionary language, thereby making it 

possible for a single product to satisfy—simultaneously—the 

terms of both definitions. SMDA § 16(b)(1), 104 Stat. at 4526. 

The FDA argues that, by eliminating the drug definition’s 

exclusionary language, the Congress granted it authority to 

regulate certain products as either drugs or devices. 

This argument presumes that the Congress dramatically 

expanded the FDA’s authority by deleting a phrase from a 

statutory definition. As the Supreme Court has counseled, 

“[f]undamental changes in the scope of a statute are not 

typically accomplished with so subtle a move.” Kellogg Brown

& Root Servs., Inc. v. U.S. ex rel. Carter, 575 U.S. 650, 661 

(2015). Instead, we conclude that “the removal of the 

. . . provision was more plausibly driven by” a narrower 

concern. Id. The change occurred in a section of the statute 

authorizing the FDA to “regulate products that constitute a 

combination of a drug, device, or biological product,” 

depending on “the primary mode of action of the combination 

product.” SMDA § 16(a), 104 Stat. at 4526 (codified as 

amended at 21 U.S.C. § 353(g)) (authorizing the regulation of 

“combination products”). These new provisions thus created a 
17

distinct regulatory regime that gave the Secretary flexibility to 

determine the standards for pre-market review of these 

combination products. See, e.g., 21 U.S.C. 

§ 353(g)(2)(A)(ii)(I) (entitling sponsors of combination 

products to meet with the Secretary to “address the standards 

and requirements for market approval or clearance of the 

combination product”); id. § 353(g)(7) (“Nothing in this 

subsection shall prevent the Secretary from using any agency 

resources of the [FDA] necessary to ensure adequate review of 

the safety, effectiveness, or substantial equivalence of an 

article.”). The definitional change helped to implement the 

scheme by removing the previously categorical prohibition on 

ever treating a drug as a device and vice versa. See Miller v. 

Mylan Inc., 741 F.3d 674, 677 (6th Cir. 2014) (“The deletion 

reflected the replacement of the binary scheme with a tripartite 

scheme[ that included combination products].”). But the 

amended definition provides no affirmative support for the 

proposition that the FDA may treat drugs as devices—and vice 

versa—even absent any combination. As explained above, the 

FDCA’s basic textual architecture forecloses such reading of 

the statute. 

Legislative history confirms that the amendments seek 

only to facilitate the FDA’s regulation of the new category of 

“combination products.”5 See S. Rep. No. 101-513, at 43 

(1990) (“Section 19 [of the SMDA] alters the drug and device 

definitions in [21 U.S.C. § 321]. Language is removed from 

the drug definition that will permit an approval of a 

drug/device combination.”) (emphasis added); id. at 30 (“By 

deleting this language, a product whose primary mode of action 

5 We note that our analysis of the FDA’s argument regarding 

the 1990 SMDA depends upon the FDCA’s legislative history, which 

we further discuss in the following section, infra Section II.B. 

Because the FDA’s SMDA argument is primarily textual, we address 

it here.
18

is attributable to a drug, but has a device component, may be 

reviewed under this Act’s drug authority.”). Thus, we read the 

SMDA to facilitate the regulation of combination products, not

to grant the FDA near-limitless discretion to categorize as 

drugs any product meeting the device definition.6

B. FDCA’s Structure, Purpose and Legislative History

We turn next to the FDCA’s structure, purpose and 

legislative history. See, e.g., Pharm. Rsch. & Mfrs. of Am. v. 

Thompson, 251 F.3d 219, 224 (D.C. Cir. 2001); see also 

Roberts v. Sea-Land Servs., Inc., 566 U.S. 93, 101 (2012) 

(“[Because s]tatutory language . . . ‘cannot be construed in a 

vacuum . . . [i]t is a fundamental canon of statutory construction 

that the words of a statute must be read in their context and with 

a view to their place in the overall statutory scheme.’”) 

(quoting Davis v. Mich. Dep’t of Treasury, 489 U.S. 803, 809 

(1989)). All of these considerations reinforce our conclusion. 

As set out above, supra Section I.A, the FDCA establishes 

two distinct regulatory tracks, one for drugs and one for 

devices. Although certain aspects of the regulatory regimes are 

common, see, e.g., 21 U.S.C. § 352 (defining a single standard 

by which “[a] drug or device shall be deemed to be 

misbranded”), several vital aspects are not. Especially salient 

here are the FDCA’s dual regimes for pre-market review and 

approval. Subject to limited exceptions, new drugs require pre6 The concurring opinion reads the amendment as “just the kind 

of ‘textual indication’ that may override” the general-specific canon. 

See Concurring Op. 6–7 (alteration adopted) (quoting RadLAX 

Gateway Hotel, 566 U.S. at 646). But deleting the express exclusion 

from the drug definition only raised the general-specific question

without answering it. And as discussed, we decline to embrace such 

a large grant of authority from a negative inference in statutory 

history.
19

market approval based upon clinical showings of safety and 

efficacy, see 21 U.S.C. § 355(a)–(b), while devices are subject 

to varying levels of pre-market review depending upon the risk 

they pose. Only Class III devices—so classified because they 

“present[] a potential unreasonable risk of illness or injury” or 

because they are “purported or represented to be for a use in 

supporting or sustaining human life or for a use which is of 

substantial importance in preventing impairment of human 

health,” id. § 360c(a)(1)(C)—generally require pre-market 

approval. Id. § 360e. Nor is the FDA’s authority over the 

classification of devices entirely unfettered. The FDA is 

required to convene expert panels to provide recommendations 

on its device classification decisions, id. § 360c(b), and device 

sponsors are entitled to participate in the classification process. 

Id. § 360c(b)(6). It would make little sense, then, for the 

Congress to have constructed such elaborate regulatory 

regimes—carefully calibrated to products’ relative risk 

levels—only for the FDA to possess the authority to upend the 

statutory scheme by reclassifying any device as a drug, no 

matter its relative risk level.

The legislative history underscores our analysis. As 

discussed above, see supra Section I.A, setting aside products 

that are not “an instrument, apparatus, implement, machine, 

contrivance, implant, in vitro reagent, or other similar or related 

article,” 21 U.S.C. § 321(h)(1), what distinguishes a drug from 

a device under the FDCA is that a device excludes a product 

that achieves its primary intended purposes through either 

chemical action or metabolization. This, however, was not 

always the case. The two mode-of-action clauses were added 

to the FDCA’s device definition by the Medical Device 

Amendments of 1976 (MDA), Pub. L. No. 94-295, 90 Stat. 

539, and the legislative history strongly suggests that the 

Congress’s aim, at least in part, was to formalize a 

distinction—apparently already “administratively developed” 
20

by the FDA—between drugs and devices based upon their 

modes of action and the relative risk levels created by those 

modes of action. See S. Rep. No. 94-33, at 6 (1975) (explaining

that the “FDA has administratively developed a distinction 

between drug and device, which favors classifying a product as 

a drug if its intended action is chemical, or based on highly 

complex technology potential hazards of which may be 

reduced through new drug controls”). Granted legislative 

history is hardly dispositive, but we nonetheless see in it 

additional evidence that the Congress established separate

regulatory tracks for drugs and devices and that the device 

definition’s mode-of-action clauses were critical to 

effectuating this bifurcated scheme. 

The FDA offers its own arguments regarding the FDCA’s 

statutory structure but none is compelling. Specifically, the 

FDA directs our attention to two provisions of the FDA 

Reauthorization Act of 2017 (FDARA), Pub. L. No. 115-52, 

131 Stat. 1005, both of which relate to the marketing of a 

medical imaging device intended for use with a prior-approved 

contrast agent but the contrast agent’s new intended use is 

different from the prior-approved intended use. The first 

provision grantsthe FDA authority to approve certain “medical 

imaging device[s]” notwithstanding they “involve[] the use of 

a contrast agent” in a manner different from that described in 

the agent’s approved labeling. Id. § 706(a), 131 Stat. at 1058–

59 (codified at 21 U.S.C. § 360j(p)). The FDA latches onto 

language in this provision defining a “contrast agent,” in 

relevant part, as “a drug that . . . is intended for use in 

conjunction with an applicable medical imaging device . . . .” 

Id. § 706(a), 131 Stat. at 1059 (emphasis added) (codified at 21 

U.S.C. § 360j(p)(4)(B)). The second provision grants the FDA 

authority to approve a contrast agent’s new intended use based 

upon the submission of a supplement to the sponsor’s original 

new drug application. Id. § 706(b), 131 Stat. at 1059–60 
21

(codified at 21 U.S.C. § 355(y)). The FDA argues that both 

FDARA provisions evince a congressional intent to ratify the 

FDA’s practice of uniformly regulating all contrast agents as 

drugs. 

Despite its superficial appeal, the FDA’s argument is 

unavailing. First, the FDARA’s definitional language—

defining a contrast agent as “a drug”—was explicitly provided 

“[f]or purposes of this subsection . . . .” Id. § 706(a), 131 Stat. 

at 1059 (emphasis added) (codified at 21 U.S.C. § 360j(p)(4)). 

Subsection 360j(p) authorizes treating as devices the 

combination of imaging devices paired with contrasting agents 

previously approved as drugs. 21 U.S.C. § 360j(p). But some 

contrast agents work through chemical action within the body 

and thus plainly are drugs. See id. § 321(h)(1). The special 

rules provided in this context thus hardly suggest that the FDA 

may generally treat all contrast agents as drugs, much less 

constitute “express congressional approval” for such a rule. 

Gen. Am. Transp. Corp. v. ICC, 872 F.2d 1048, 1053 (D.C. Cir. 

1989) (quoting AFL-CIO v. Brock, 835 F.2d 912, 915 (D.C. 

Cir. 1987)). The second provision cited by the FDA, 21 U.S.C. 

§ 355(y), likewise governs contrast agents previously approved 

as drugs, which does not suggest that all contrast agents must 

(or even may be) so classified. Even more fundamentally, we 

strongly doubt that the Congress would have chosen to hide 

such a major grant of regulatory discretion in so narrow an 

amendment. Had it intended to endorse the view that the FDA 

may regulate all contrast agents as drugs rather than devices, it 

would have used more explicit language to do so. Here as 

elsewhere we “must be guided to a degree by common sense as 

to the manner in which Congress is likely to delegate a policy 

decision of such economic and political magnitude to an 

administrative agency” and we are skeptical that the Congress 

would grant the FDA such vast authority “in so cryptic a 
22

fashion.” FDA v. Brown & Williamson Tobacco Corp., 529 

U.S. 120, 133, 160 (2000).

The FDCA’s structure, purpose and legislative history

confirm our reading of the text. See Teva Pharms., 595 F.3d at 

1315 (analyzing statutory structure and setting aside FDA’s 

interpretation of FDCA where text alone “hardly rules out 

alternative readings that, absent consideration of statutory 

structure, also appear plausible”). They make plain that the 

Congress did not grant the FDA near-limitless discretion to 

classify any device as a drug. Rather, the Congress has 

elaborated separate regulatory tracksfor drugs and devices and,

to the extent that the FDA possesses the discretion to choose 

one track or the other, such discretion must be exercised in a 

manner consistent with the statutory “drug” and “device” 

definitions. 

We note that we are especially troubled by the FDA’s 

inability to articulate a limiting principle with which to cabin 

its asserted discretion. The FDA offers only that, like all other 

agency actions, its classification decisions are subject to the 

APA’s arbitrary and capricious standard. But the arbitrary and 

capricious standard is necessarily narrow, see Motor Vehicle 

Mfrs. Ass’n of U.S., Inc. v. State Farm Mut. Auto. Ins. Co., 463 

U.S. 29, 43 (1983), and seldom is that more true than in the 

context of highly technical matters like the FDA’s medical 

product classifications, see, e.g., Kennecott Greens Creek Min. 

Co. v. Mine Safety & Health Admin., 476 F.3d 946, 954–55 

(D.C. Cir. 2007) (agency is entitled to “extreme degree of 

deference” when “evaluating scientific data within its technical 

expertise”) (quoting Hüls Am. Inc. v. Browner, 83 F.3d 445, 

452 (D.C. Cir. 1996)). Thus, what the FDA attempts to claim 

for itself is the near-limitless authority to classify any device as 

a drug, subject only to a highly deferential standard of judicial 

review. We cannot reasonably infer such broad discretion 
23

without a clearer statement. See Whitman v. Am. Trucking 

Ass’ns, Inc., 531 U.S. 457, 467–68 (2001) (“Congress, we have 

held, does not alter the fundamental details of a regulatory 

scheme in vague terms or ancillary provisions—it does not, one 

might say, hide elephants in mouseholes.”).7

The concurring opinion stresses the need for the FDA to 

bring its expertise to bear on close questions regarding whether 

the instrument clause covers particular kinds of medical 

products. Concurring Op. 11–14. We do not deny that when 

the instrument clause (and, for that matter, the mode-of-action 

clauses) are ambiguous in their application to some kind of 

medical product, reviewing courts should respectfully consider 

the expert views of the FDA, which may even qualify for 

Chevron deference. But here, the FDA did not invoke its 

expertise to contend that Vanilla SilQ does not satisfy the 

device definition and so should be regulated as a drug. Instead, 

it assumed that Vanilla SilQ meets the definition of a device 

but nevertheless undertook to regulate it as a drug. In rejecting 

that position, we do nothing to restrict the agency’s discretion 

to determine, in close cases, whether a particular product 

satisfies the device definition. Indeed, we expressly reserve 

that question in this case. See supra n.3. 

We emphasize the purely legal nature of the question 

before us. Because its interpretation of the FDCA did not 

require it to do so, the FDA made no factual findings with 

respect to Vanilla SilQ except that it is an article intended for 

use in the diagnosis, cure, mitigation, treatment or prevention 

7 We also disagree that the FDA’s restrained use of discretion in the 

past blunts this concern or otherwise provides a basis to limit any

purported discretion. See Carlson v. Postal Reg. Comm’n, 938 F.3d 

337, 349 (D.C. Cir. 2019) (“[N]o amount of historical consistency 

can transmute an unreasoned statutory interpretation into a reasoned 

one.” (internal quotations omitted)).
24

of disease—that is, the minimum findings necessary for 

classification as a drug. We do not and cannot consider

whether the FDA’s assumption that Vanilla SilQ satisfies the 

device definition is a valid one because it was not the basis for 

the FDA’s decision. See SEC v. Chenery Corp., 318 U.S. 80, 

93–94 (1943). Instead, we necessarily address only the FDA’s 

conclusion that the FDCA grants it discretion to classify as a 

“drug” any product that meets the statutory definition of a 

“device.” We hold that it does not. Excepting combination 

products, see 21 U.S.C. § 353(g), devices must be regulated as 

devices and drugs—if they do not also satisfy the device 

definition—must be regulated as drugs.8 Thus, the FDA’s 

decision must be set aside because it was based on an erroneous 

interpretation of law. See 5 U.S.C. § 706(2). 

For the foregoing reasons, the judgment of the district 

court is affirmed. 

So ordered.

8 Our reading does not, as the concurring opinion suggests, limit the 

drug definition “to products with the modes of action specified in the 

device definition’s exclusions.” Concurring Op. 14. A product that 

satisfies the drug definition and the mode-of-action clauses in the 

device definition would still be a drug if it could not satisfy the 

instrument clause. 
PILLARD, Circuit Judge, concurring in the judgment: Our 

role on review is limited to determining whether Congress has 

unambiguously foreclosed the FDA’s statutory interpretation, 

and, if not, whether the agency’s decision is nonarbitrary and 

reasonably explained. In regulating Vanilla SilQ as a drug, the 

FDA asserted that the FDCA’s drug definition fully subsumes 

the device definition so grants the FDA authority to regulate 

any device as a drug. See J.A. 121-22; Appellant’s Br. 6-7, 15-

17. Vanilla SilQ is a contrast agent used in radiologic 

procedures including X-rays. The mode of action of some 

other contrast agents prevents their regulation as devices. 

Because the agency deemed it administratively convenient to 

regulate Vanilla SilQ together with other contrast agents, 

whatever their mode of action, it decided to regulate Vanilla 

SilQ under the drug regime. See J.A. 122 & n.5.

The majority acknowledges that the text of the drug and 

device definitions describes some overlap. See Maj. Op. 4, 13.

But, cued by the FDA’s overbroad claim of discretion, my 

colleagues view the textual overlap as conferring implausibly 

“sweeping,” “near-limitless” power on the FDA to regulate any 

device as a drug, contrary to the congressional scheme. Id. at 

3, 18, 22. Cognizant that Congress defined devices separately 

from drugs for important reasons, the majority resorts to 

statutory structure and history to conclude that the drug and 

device definitions overlap not at all, so are entirely mutually 

exclusive. Id. at 11, 14-15, 17-18, 22, 24.

I agree with my colleagues that the FDA misread the 

statute in concluding that the drug definition fully subsumes 

devices. But I join the judgment only, because the majority 

overshoots in the other direction by insisting the statute 

unambiguously eliminates all overlap of the drug and device 

definitions. There is overlap, but it is only partial. 

Both the FDA’s and my colleagues’ readings overtly 

disregard textual specificity within the device definition that 
2

assigns particular types of products to the regulatory pathway 

for devices, not drugs. Whereas the drug definition refers to 

“articles” intended for medical uses, 21 U.S.C. § 321(g)(1)(B),

the device definition singles out as devices any “instrument, 

apparatus, implement, machine, contrivance, implant, in vitro 

reagent, or other similar or related article, including any 

component, part, or accessory,” intended for those same uses,

id. § 321(h)(1). That more specific list—the “instrument 

clause,” for short—communicates Congress’s intent not to 

grant the FDA the broad discretion it claims. The FDA is 

wrong to view the device definition as describing a fully nested 

subset of the drug definition; it clearly prevents assignment of 

many devices—from bathroom scales and band-aids to 

respirators and ultrasound machines—to the regulatory 

pathway for drugs.

The FDA has yet to grapple with the product 

characteristics Congress deemed relevant. The agency simply 

assumed that Vanilla SilQ meets the device definition. It 

treated the instrument clause as a nullity and proceeded as if 

the mode-of-action exclusions did not apply to Vanilla SilQ. 

See Appellant’s Br. 21; J.A. 121-22, 152; see also Oral Arg. 

Tr. 5:10-6:12. It neither identified in what respect Vanilla SilQ

might or might not be considered an “instrument,” nor verified 

how it avoids the device definition’s mode-of-action 

exclusions. The agency accordingly failed to explain its 

decision to regulate Vanilla SilQ as stringently as a drug in any

way that accounts for the factors Congress deemed relevant to 

its design of distinct drug and device regimes. The explanation 

it did provide, turning on little more than administrative 

convenience, falls short, so requires remand to the FDA. That 

is as far as we need to go to decide this case.
3

I.

Our review of the FDA’s classification decision pursuant 

to the FDCA turns on “whether Congress has unambiguously 

foreclosed the agency’s statutory interpretation.” Vill. of 

Barrington v. Surface Transp. Bd., 636 F.3d 650, 659 (D.C. 

Cir. 2011) (internal quotation marks and citation omitted). “If 

the agency’s interpretation is not unambiguously foreclosed by 

the statute, we defer to its interpretation so long as it is 

reasonable.” Sorenson Commc’ns, LLC v. FCC, 897 F.3d 214, 

224 (D.C. Cir. 2018) (internal quotation marks and citation

omitted); see also Serono Lab’ys, Inc. v. Shalala, 158 F.3d 

1313, 1319-22 (D.C. Cir. 1998) (applying that framework to 

the FDA’s interpretation of the FDCA). We cannot defer to an 

agency decision that rests on an erroneous statutory 

interpretation.

Our deference to the agency depends on its having 

engaged in reasoned decisionmaking, explaining how it 

accounted for all the factors relevant to the exercise of the 

authority Congress has given it. See Judulang v. Holder, 565 

U.S. 42, 53 (2011); 5 U.S.C. § 706(2). We cannot sustain a 

ruling that fails to consider and explain an important aspect of 

the issue at hand. Motor Vehicle Mfrs. Ass’n of U.S., Inc. v. 

State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43 (1983); see 

also Pharm. Mfg. Rsch. Servs., Inc. v. FDA, 957 F.3d 254, 262 

(D.C. Cir. 2020) (applying that standard to FDA action taken 

pursuant to the FDCA).

The bulk of my colleagues’ analysis trains on the 

functional separation and mandatory character of the drug and 

device regulatory pathways. But nobody questions that, when 

faced with a product with the intended use common to both the 

drug and device definitions—i.e., a product intended for use in 

the diagnosis, cure, mitigation, treatment, or prevention of 
4

disease—the agency must regulate it as either a drug or a 

device, not both. See Appellant’s Br. 16-17, 25-26; Maj. Op. 

14-15. And all agree that the respective drug and device 

regimes are mandatory on the agency and the regulated parties. 

See Oral Arg. Tr. 9:18-10:9; Maj. Op. 15. The dispute here is 

whether the statute does all the work of sorting drugs from 

devices or whether it affords the agency some discretion in 

doing so and, if the latter, how much and with what guideposts.

The FDA claims leeway well beyond what the statute 

affords. My colleagues overlook definitional overlap the 

statute allows. I start with the overlap the majority denies, and 

then discuss how the FDA’s discretion is bounded in ways the 

agency overlooks. I defend Congress’s decision to allow for 

some overlap in the drug and device definitions in view of the 

complexity and heterogeneity of medical products and the 

challenge of assessing their efficacy and safety.

A.

The Supreme Court has long acknowledged “obvious 

areas of overlap in definition” of drugs and devices under the 

FDCA, even under an earlier version of the statute that 

manifested exclusivity in a way that it does not today. United 

States v. Article of Drug, Bacto-Unidisk, 394 U.S. 784, 799

(1969). Congress codified a particular definitional overlap in 

1990, when it cut from the drug definition its prior, express 

exclusion of “devices or their components, parts, or 

accessories.” Safe Medical Devices Act of 1990 (SMDA), 

Pub. L. No. 101-629, § 16(b)(1), 104 Stat. 4511, 4526. It did 

so to clearly permit the FDA to regulate as drugs some products 

also meeting the device definition. The products foremost on 

the congressional agenda at that time were “combination 

products”—such as surgical mesh with anesthetic coating and 

drug-eluting cardiovascular stents that are “instruments” as 
5

referenced in the device definition but that also function in part 

through chemical action or metabolization that would define 

them as drugs. Capsular Decisions – Products Assigned to 

CDRH, FDA (Feb. 16, 2018), 

https://www.fda.gov/combination-products/rfd-jurisdictionaldecisions/capsular-decisions-products-assigned-cdrh. But the 

SMDA did not limit the amendment to those products, so we 

have no business doing so.

The majority insists Congress removed the drug category’s 

exclusion of devices “only to facilitate the FDA’s regulation of 

the new category of ‘combination products.’” Maj. Op. 17. 

But it is the enacted text “rather than the principal concerns of 

our legislators by which we are governed.” Bostock v. Clayton 

County, 140 S. Ct. 1731, 1749 (2020) (quoting Oncale v. 

Sundowner Offshore Servs., Inc., 523 U.S. 75, 79 (1998)). 

“The fact that Congress may not have foreseen all of the 

consequences of a statutory enactment is not a sufficient reason 

for refusing to give effect to its plain meaning.” Union Bank v. 

Wolas, 502 U.S. 151, 158 (1991); see Antonin Scalia & Bryan 

A. Garner, Reading Law: The Interpretation of Legal Texts 56 

(2012) (“[T]he purpose must be derived from the text, not from 

extrinsic sources such as legislative history or an assumption 

about the legal drafter’s desires.”). Congress easily could have 

limited the scope of the amendment as the majority says it 

meant to do by writing it as an exception within the new 

provision for combination products, 21 U.S.C. § 353(g), 

relieving only combination products’ device components from 

the drug definition’s exclusion. Instead, Congress removed the 

device exclusion altogether.1 It thus did not enact the mutual

1 Even in referencing combination products, the legislative 

history does not describe the amendment as confined to them. See

S. Rep. No. 101-513, at 43 (1990) (explaining that Congress removed 

the device exclusion from the drug definition to “permit” 

combination products); id. at 30 (explaining that the amendment 
6

exclusivity of the statute’s drug and device definitions that my 

colleagues detect.

The majority sees the device definition’s mode-of-action 

exclusions as “critical to effectuating” non-overlapping 

statutory drug and device definitions. See Maj. Op. 20; see also

Oral Arg. Tr. 29:2-17 (Genus arguing that the mode-of-action 

clauses are what distinguish drugs from devices). But those

exclusions do not unambiguously remove definitional overlap. 

They prevent regulation of a product as a “device” insofar as it 

“achieve[s] its primary intended purposes through chemical 

action within or on the body of man or other animals” or is

“dependent upon being metabolized for the achievement of its 

primary intended purposes.” 21 U.S.C. § 321(h)(1). But by 

their terms those exclusions operate only in one direction: The 

text nowhere provides that the drug definition is confined to 

products reliant on the modes of action that the device 

definition excludes. Definitional overlap remains for products

that do not achieve their primary intended purposes by 

chemical or metabolic action—a category that the FDA here 

assumed without deciding includes Vanilla SilQ.

The general-governs-the-specific canon on which the 

majority’s reading depends is not to the contrary. See Maj. Op. 

13-15. That canon is “a strong indication of statutory meaning” 

but “not an absolute rule.” RadLAX Gateway Hotel, LLC v. 

Amalgamated Bank, 566 U.S. 639, 646 (2012). It cannot 

resolve all cases when the more specific provision is as 

qualitative as the device definition’s instrument clause. (More 

on that below.) Plus, the partial overlap wrought by the 1990 

Amendment is just the kind of “textual indication[]” that may 

ensured that drugs with device components “may be reviewed” as 

drugs).
7

override the canon in a case in which the agency provides 

sufficient explanation. Id.

Neither the mode-of-action exclusions nor the 1990 

Amendment requiresthat Vanilla SilQ be regulated as a device. 

Nor do they together effectuate mutual exclusivity of the drug 

and device definitions.

B.

At the same time, acknowledgment of the statutory drug 

and device definitions’ overlap—and the FDA’s factual 

assumption that Vanilla SilQ falls within it—does not suffice 

to allow the FDA to classify the product as a drug. The agency

claims that, apart from products the mode-of-action clauses

identify as drugs, any product with the requisite intended use 

may be regulated as either a device or a drug. But the FDA is 

wrong that the mode-of-action exclusions are the only relevant 

constraint. See Appellant’s Br. 6-7; see also Oral Arg. Tr. 

5:10-6:12, 48:20-23. The device definition also has 

inclusionary language, defining a product as a device if it is an 

“instrument, apparatus, implement, machine, contrivance, 

implant, in vitro reagent, or other similar or related article, 

including any component, part, or accessory.” 21 U.S.C. 

§ 321(h)(1).

The FDA sees “device” as a fully nested subset of “drug” 

by noting that the general reference to “articles” in the drug 

definition, id. § 321(g)(1), is broad enough to subsume every 

“instrument, apparatus, . . . or other similar or related article” 

listed in the device definition’s instrument clause, id.

§ 321(h)(1). See Appellant’s Br. 6-7; Oral Arg. Tr. 8:12-20. 

Genus agrees, at least when it comes to the instrument clause. 

See Oral Arg. Tr. 29:2-17 (noting that both definitions use the 

term “articles,” and that the statute distinguishes them with the 

device definition’s mode-of-action clauses). That reading is 
8

impermissible. “A statute should be construed so that effect is 

given to all its provisions, so that no part will be inoperative or 

superfluous, void or insignificant.” Corley v. United States, 

556 U.S. 303, 314 (2009) (citation omitted and formatting 

modified). The FDA violates the canon against superfluity by

failing to give meaning to a big piece of the device definition.

The only argument the FDA puts forward is that its reading 

creates no superfluity because the two definitions remain 

distinct: “Products that satisfy the ‘device’ definition may be 

regulated either as drugs or as devices, whereas those that 

satisfy the ‘drug’ definition but not the ‘device’ definition may 

be regulated only as drugs.” Appellant’s Br. 16. But that 

misses the point. It does nothing to explain why Congress used 

twenty words in the device definition’s instrument clause if it 

meant nothing more specific than is expressed by the word 

“articles” alone in the drug definition.

Notwithstanding that the FDA treats it as a nullity here, the 

instrument clause has all along done substantial work in 

assigning products to the device rather than the drug pathway. 

For starters, the FDA accounts for that clause in classifying as 

devices all manner of medical products, such as crutches, Xray machines, and other “things that go clank.” Oral Arg. Tr. 

6:3; see, e.g., 21 C.F.R. § 890.3150 (classifying a crutch as a 

device); id. § 892.1680 (classifying a stationary X-ray system 

as a device). With the instrument clause in view, it is obvious 

that the statute does not afford the agency the “near-limitless 

discretion,” Maj. Op. 18, 22, that the FDA says it does and that

animates the majority’s too-restrictive response, see id. at 16 

(voicing concern that the 1990 Amendment “dramatically 

expanded” the FDA’s authority). The instrument and modeof-action clauses make clear the elephant that the majority sees 

is only a mouse. See id. at 23 (citing Whitman v. Am. Trucking 

Ass’ns, Inc., 531 U.S. 457, 467-68 (2001)).
9

In the decades since Congress in 1990 removed the device 

exclusion from the FDCA’s drug definition to create some 

textual overlap, there is little evidence that the FDA has treated

as drugs what should be regulated as devices. See Oral Arg. 

Tr. 11:21-23 (FDA referencing the lack of cases); cf. Bracco 

Diagnostics, Inc. v. Shalala, 963 F. Supp. 20, 28 (D.D.C. 1997)

(saying of contrast agents that “all likely meet both . . . 

definition[s] . . . and the FDA therefore has discretion in 

determining how to treat them,” though it cannot “permit two 

sets of similar products to run down separate tracks . . . for no 

apparent reason”). The only other instance the parties identify

of a product that meets the device definition but that the FDA 

nonetheless regulates as a drug is sunblock. As with contrast 

agents, the FDA uniformly regulates the entire group of 

sunscreen products as drugs even though some, “such as those 

commonly marketed for use with infants and small children,” 

are also eligible to be regulated as devices insofar as they 

operate by providing a physical barrier (e.g., zinc) against solar 

rays, rather than through chemical action that would subject 

them to the device definition’s mode-of-action exclusion. 

Appellant’s Br. 31-32; see also Appellee’s Br. 47. The dearth 

of litigated cases, or even illustrative examples, of products

arguably meeting the device definition but being regulated as 

drugs owes much to the instrument clause. 

The FDA here treats the instrument clause as superfluous, 

but its own guidance and regulations recognize the clause’s

robust role informing the FDA’s product classifications. The 

FDA’s 2017 Guidance points out that, “[i]n some cases,”

products that are not themselves instruments, apparatuses, or 

so forth “are appropriately considered ‘similar or related 

articles’” under the instrument clause “and may be classified as 

devices.” J.A. 332. It notes how, for example, “gels or 

powders put on the skin” come within the instrument clause

when used “as a barrier,” “gases” satisfy the clause when “used 
10

as space fillers,” and certain “liquids” qualify when “used to 

clean either surgical instruments or contact lenses.” Id.; see, 

e.g., 21 C.F.R. § 886.5928 (classifying “contact lens care 

products” for soft contact lenses, including solutions, as 

devices); see also Topical Drug Products for Over-the-Counter 

Human Use; Products for the Prevention of Swimmer’s Ear and 

for the Drying of Water-Clogged Ears; Final Rule, 60 Fed. Reg. 

8916, 8917 (Feb. 15, 1995) (explaining that the products at 

issue were not devices because they did not satisfy the 

instrument clause, and that they were drugs even though they 

worked through physical, not chemical or metabolic, means); 

Capsular Decisions – Products Assigned to CDER, FDA (Feb. 

16, 2018), https://www.fda.gov/combination-products/rfdjurisdictional-decisions/capsular-decisions-products-assignedcder (listing “[d]ye mouthrinse to examine oral tissue” as a 

drug).

The FDA is bound by “the core administrative-law 

principle that an agency may not rewrite clear statutory terms 

to suit its own sense of how the statute should operate.” Util. 

Air Regul. Grp. v. EPA, 573 U.S. 302, 328 (2014). Because it 

incorrectly treated the instrument clause as a nullity and 

assumed without deciding that the mode-of-action clauses do 

not apply to Vanilla SilQ, see Appellant’s Br. 21 (citing J.A. 

122), the agency concluded the statute was silent as to whether 

Vanilla SilQ should be regulated as a drug or device. With 

none of the device definition’s clauses placing any restriction 

on its action here, the FDA says, it had free rein to choose how 

to regulate Vanilla SilQ, and it chose the drug pathway. See id.

at 15-18. 

The FDA is not entirely wrong that the drug and device 

definitions overlap—they do, in part. But it fell short in neither 

acknowledging the detailed instrument clause nor providing a 

lawful and nonarbitrary explanation of whether and how 
11

regulating Vanilla SilQ as a drug accords with both that clause 

and the mode-of-action exclusions in the device definition. It

is no answer that the FDA’s classification decisions are subject 

to APA review, nor that its thousands of duly promulgated 

product classifications constrain its decisions as a practical 

matter. See Oral Arg. Tr. 16:12-17:7. The statutory framework 

governing the FDA’s exercise of its discretion is what provides 

traction for those procedural safeguards—and the instrument 

clause that the agency ignored here is a crucial part of that 

framework. 

We have said, in relation to the FDCA, that a “statutory 

phrase must be read in the context of the kind of drug at issue.” 

Serono Lab’ys, 158 F.3d at 1319. The FDA’s interpretation of 

the drug and device definitions and their application to Vanilla 

SilQ failed even “to wrestle with the relevant statutory 

provisions,” including the instrument clause, and “we cannot 

do [the agency’s] work for it.” Hosp. of Barstow, Inc. v. NLRB, 

820 F.3d 440, 445 (D.C. Cir. 2016) (quoting Children’s Hosp. 

& Rsch. Ctr. of Oakland, Inc. v. NLRB, 793 F.3d 56, 59 (D.C. 

Cir. 2015)). We are therefore “left wondering how the 

[agency] in these circumstances interprets the statute”—that is, 

how it would account for the instrument clause as a limit on the 

definitional overlap and a constraint on its discretion. Id.

(internal quotation marks omitted). Because of that 

uncertainty, I would follow “[o]ur general practice in these 

sorts of situations” and remand for the agency to interpret the 

statute in the first instance, including the instrument clause that 

it simply did not apply. Id.

C.

The nub of my disagreement with the majority concerns 

whether, as between dueling statutory definitions, the correct 

choice might legitimately turn in part on the agency’s expert 
12

determination of predicate facts and its sound discretion as to 

which definition best applies. It seems unremarkable to me that 

Congress conferred such authority on the FDA.

The majority disagrees. It concludes that, because the 

FDCA “elaborates distinct regulatory regimes” in which “each 

scheme is mandatory” for the agency and regulated parties, 

Maj. Op. 15, there can be no definitional overlap of the drug 

and device categories. Where the text does not clearly 

eliminate overlap, the majority says that interpretive canons 

make the definitions’ mutual exclusivity unmistakable. But the 

premise that the statute makes sense only if there is no 

definitional overlap is wrong.

There is no escaping some classificatory judgment by the 

FDA. To see why, it is helpful to identify two layers of 

judgment that can be required to apply the right definition to a 

given product. My colleagues take no issue with the first, but

hold that the second is inimical to the statutory structure and 

function. But the two are not materially different. Both call 

for expert determinations and judgments by the agency—

choices that the statutory scheme as written does not obviate 

and that, no matter how much detail Congress might add, could 

not be wholly eliminated. 

First, even accounting for textual specificity the FDA 

ignores, gray areas remain. With the help of the instrument and 

mode-of-action clauses, applied in relation to a product’s 

intended use, most products can readily be identified as either 

a drug or a device. But classification is not always obvious. 

Nor could it be. The drug and device definitions—in relevant 

part, each a single sentence—apply to many thousands of 

widely heterogeneous products. Those products present varied 

and often complex questions of safety and efficacy. 

Determining the appropriate scrutiny—as drug or device—can 
13

be complicated by the detailed knowledge and experience and 

the high stakes involved in assessing certain products’ efficacy 

and safety for use in the diagnosis, cure, mitigation, treatment, 

or prevention of disease. Congress knew it could not codify all 

that distinguishes drugs from devices. It was content to sketch 

the basics and leave it to the FDA to bring to bear the distinct 

expertise of the Center for Drug Evaluation and Research and 

the Center for Devices and Radiological Health, informed by 

the detailed input of many expert panels and advisory 

committees. See id. at 4-5; see also Advisory Committees, 

FDA, https://www.fda.gov/advisory-committees (last visited 

Apr. 14, 2021).

As already discussed, the instrument clause contains 

material specificity. But, at the end of the day, its terms are 

unavoidably qualitative and imprecise. For example, deciding 

whether a product is a “contrivance” or “apparatus”—let alone 

“similar or related” to one—requires some judgment about the 

product’s character. That judgment is not unguided but, per the 

FDCA and APA, informed by whether treating it as a drug or 

device best aligns with what Congress meant to achieve in 

articulating separate definitions keyed to distinct regulatory 

approaches. Also relevant is how the product compares to 

others already classified, not least because the agency acts 

arbitrarily if it regulates similar products differently. But there 

is no avoiding the exercise of judgment at the margins. 

Provided the agency makes nonarbitrary determinations based 

on substantial evidence, we must defer. My colleagues express 

no disagreement with this. See Maj. Op. 8 n.3 (noting that it is 

“not immediately obvious” how a contrast agent satisfies the 

device definition’s instrument clause, “[n]or is it altogether 

settled that Vanilla SilQ satisfies the device definition’s modeof-action clauses”); id. at 23 (acknowledging that, when the 

instrument and mode-of-action clauses “are ambiguous in their 
14

application to some kind of medical product, reviewing courts 

should respectfully consider the expert views of the FDA”).

A second layer of classification judgment, called into play 

by definitional overlap, is what the majority reads the statute to 

unambiguously eliminate. If a product is neither clearly within 

or outside the instrument clause, for example, and not excluded 

by the mode-of-action clauses, as a definitional matter it is 

plausibly both a drug and device. Even though it ultimately 

can only be regulated as one or the other, the statute does not 

alone determine which one it is. Assume, for example, that 

nanotechnology ingested or injected for the purpose of 

delivering light to cancer cells is not excluded from regulation 

as a device because it relies not on chemical action, but on some 

purely physical process. On my colleagues’ reading, that 

product could be regulated only as a device. Provided that it 

might plausibly be thought to fall within the instrument clause, 

they would hold that the device definition’s mode-of-action

clauses—“critical to effectuating” mutual exclusivity, id. at 

20—necessarily sort it into the device category. On my 

reading, the statute authorizes the FDA to make an informed 

judgment whether to regulate that type of product—rare as it 

may be—as a drug or a device. Congress did not 

unambiguously leave that call to us rather than to the FDA.

The majority’s reading has another type of anomalous 

effect. Without the overlap Congress in 1990 built into the 

definitions, an “article” that does not meet the device 

definition’s more specific “instrument” clause, and that also 

does not rely on chemical or metabolic action to achieve its 

primary intended purposes, would be neither drug nor device. 

By insisting, through negative implication, that the drug 

category is confined to products with the modes of action 

specified in the device definition’s exclusions, the majority 

eliminates coverage for any product not described as a device 
15

by the instrument clause but also not deemed a drug by the

mode-of-action clauses. For example, if Vanilla SilQ’s 

presumed mode of action were confirmed as non-chemical and 

non-metabolic, and if it were proposed to be used not for its 

arguably device-like function of blocking X-rays with its 

molecular density (and thus, e.g., an “accessory” to an X-ray 

machine) but instead to be consumed to treat disease in its own 

right (and thus an uneasy fit for “instrument”), the majority’s 

reading would exclude it from both the drug and device 

categories. Interpreting the statute to exclude a category of 

products intended for use in the diagnosis, cure, mitigation, 

treatment, or prevention of disease from both the drug and 

device definitions squarely conflicts with Congress’s design in 

a manner that acknowledging some overlap does not.

In my view, the statutory overlap effected by the 1990 

Amendment would give the FDA a choice how to classify such 

products—provided its justification addressed the product’s 

material characteristics and Congress’s definitions of the 

distinct regulatory pathways. Whether the product was 

nanotechnology or Vanilla SilQ, the agency would have to 

consider whether its device-like character and function as it is 

intended to be used suggest it should be grouped with devices. 

It would have to analyze whether its mode of action, even if not 

chemical or metabolic, presents questions of efficacy or risk 

that warrant regulating it on the same pathway with otherwise 

similar products that have different modes of action. And it 

would have to explain how its judgments on those points 

accorded with the text, nature, and purpose of the distinct 

definitions to advance the statute’s objectives. 

These two types of classificatory judgments—at the 

margins of definitions, and in the overlap between them—are 

not all that different. Both depend on legal and factual 

expertise and judgment calls informed by scientific and 
16

regulatory experience. The majority accepts the first kind yet

rejects the second. But Congress did not unmistakably 

eliminate the type of judgment calls that definitional overlap 

would require of the FDA. And nothing about that is 

anomalous. 

Similar judgment calls are built into multiple provisions of 

the FDCA. For example, we have observed that, “although the 

consequences of classification as a ‘drug claim’ or a ‘health 

claim’ are quite substantial”—if the former, a product would 

have to be approved as a drug to be marketed in that way—

“Congress has given definitions that at least partially overlap” 

with “little guidance as to how the FDA should sort out claims 

that seem to fit both definitions.” Whitaker v. Thompson, 353 

F.3d 947, 949 (D.C. Cir. 2004). Faced with that statutory 

overlap, we deferred to the agency’s reasonable interpretation. 

Id. at 951-52.

In Serono Laboratories, Inc. v. Shalala, we likewise

deferred to the FDA’s interpretation of an FDCA provision 

requiring the agency to approve a generic drug with the “same” 

active ingredients as a listed drug, in part because the statute 

did not foreclose treating a generic as clinically the same even 

if not completely chemically identical to the pioneer version. 

158 F.3d at 1318-20. In so holding, we emphasized the 

significant judgment that Congress entrusted to the agency in 

the FDCA: “The FDA’s determination of what is required to 

establish ‘sameness’ for purposes of the Act rests on the 

agency’s evaluations of scientific data within its area of 

expertise, and hence is entitled to a high level of deference.” 

Id. at 1320 (internal quotation marks and citations omitted). In 

sum, the majority’s statutory analysis is unpersuasive, and the 

concern that animates it illusory.
17

But because the FDA has neither recognized the statutory 

constraints that bear on its classification of Vanilla SilQ nor 

made findings on the relevant facts, I agree we must remand to 

the agency to do so.

II.

I credit the majority for recognizing a lack of clarity at the 

margins, specifically “reserv[ing] the question whether Vanilla 

SilQ satisfies the device definition’s instrument and mode-ofaction clauses” and thus not prejudging the outcome. Maj. Op. 

8 n.3; accord id. at 23. The court’s decision leaves the agency 

with several options on remand. For instance, the FDA might 

determine that Vanilla SilQ—an oral solution consumed by 

patients to improve imaging of their gastrointestinal tracts with 

X-ray machines and CT scanners—is sufficiently “related” to 

those devices or an “accessory” to them, 21 U.S.C. § 321(h)(1), 

such that it, too, is a device within the meaning of the FDCA 

and must be regulated as such. Or the FDA might make a 

contrary determination, in which case Vanilla SilQ remains

amenable to classification and regulation as a drug. And if, 

after further study, the FDA were to determine that Vanilla 

SilQ in fact achieves its primary intended purpose through 

chemical action, as an amicus urges, see Amicus Bracco Br. 5-

6, that conclusion would call for its regulation as a drug. (At 

this juncture, no one suggests that Vanilla SilQ achieves its 

primary intended purpose through metabolization, see id. at 7, 

but that possibility likewise remains open and would require 

regulation as a drug.)

That is all to say that the agency must make the requisite 

factual determinations and attend to all relevant statutory 

provisions to decide whether to classify Vanilla SilQ as either 

a drug or device in the first instance, and that it may “deal with 

the problem afresh” on remand. Dep’t of Homeland Sec. v. 
18

Regents of the Univ. of Cal., 140 S. Ct. 1891, 1908 (2020) 

(quoting SEC v. Chenery Corp., 332 U.S. 194, 201 (1947)). 

Once the FDA does the work of applying the explicit 

constraints of the device definition’s instrument and mode-ofaction clauses, it might determine that Vanilla SilQ is not a 

device, but only a drug. In that event, there would have been

no reason to address the existence or not of definitional overlap 

between drugs and devices. 

The majority goes further than required to resolve this 

appeal when it interprets the device and drug definitions as 

mutually exclusive. I have explained why the majority errs as 

a matter of statutory interpretation. More fundamentally, we 

need not—so should not—decide that issue because it is not yet 

apparent whether the existence or not of definitional overlap 

matters in the case of Vanilla SilQ. If the FDA on remand were 

to confirm that it believes that Vanilla SilQ could be either a 

device or drug and make an assignment with the proper 

reasoning in support, we would then be faced with the question 

whether statutory overlap permits it to do so, and whether its 

assignment comports with the APA. For now, it suffices to 

identify the flaws in the FDA’s decision and the inadequacy of 

the unelaborated administrative convenience rationale it gave 

for subjecting contrast agents with materially varying modes of 

action to the same degree of regulatory rigor. 

* * *

Because the FDCA does not give the FDA the discretion 

that it claims to regulate any device as a drug, and the agency 

has failed to explain its choice in a manner that grapples with 

the applicable statutory terms, I concur in the court’s judgment.