147 
 
Guidance for Industry 
 
 
Studies to Evaluate the Safety of Residues of 
Veterinary Drugs in Human Food: 
Repeat-Dose (90-Day) Toxicity Testing 
VICH GL31 
 
Final Guidance 
(This version of the guidance replaces the version that was made available in 
November 12, 2003. This guidance document has been revised to correct the contact 
information in regard to this document.) 
 
The objective of this guidance is to establish recommendations for an internationally 
harmonized 90-day repeat-dose testing 
 
Comments and suggestions regarding the document should be submitted to Division of 
Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, 
Rm.  1061,  Rockville,  MD    20852.  Submit  electronic  comments  to 
http://www.regulations.gov.   All comments should be identified with the Docket No. 02D-
0368.   
 
For questions regarding this document, contact the Division of Human Food Safety, Center 
for Veterinary Medicine, (HFV-150), Food and Drug Administration, 7500 Standish Place, 
Rockville, MD 20855, 240-276-8208. 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Veterinary Medicine 
July 27, 2006  Contains Non-Binding Recommendations 
 
GL31 (SAFETY: REPEAT-DOSE (90-DAY) TOXICITY) 
October 2002 
For implementation at Step 7 - Final 
 
 
 
 
 
S  
TUDIES TO EVALUATE 
 
THE SAFETY OF RESIDUES OF
V D H  
  ETERINARY  RUGS IN  UMAN
F : 
  OOD
R -D (90-D ) 
EPEAT OSE  AY
T T  
  OXICITY  ESTING
 
 
 
 
Recommended for Implementation 
on October 2002 
by the VICH Steering Committee 
 
 
 
 
 
 
 
 
 
 
THIS GUIDANCE HAS BEEN DEVELOPED BY THE APPROPRIATE VICH EXPERT WORKING GROUP AND 
WAS SUBJECT TO CONSULTATION BY THE PARTIES, IN ACCORDANCE WITH THE VICH PROCESS. AT 
STEP 7 OF THE PROCESS THE FINAL DRAFT IS RECOMMENDED FOR ADOPTION TO THE REGULATORY 
BODIES OF THE EUROPEAN UNION, JAPAN AND USA. 
 
 
Page 2 
  Contains Non-Binding Recommendations 
 
REPEAT-DOSE (90-DAY) TOXICITY TESTING 
 
 
 
 
TABLE OF CONTENTS 
 
 
 
1.  INTRODUCTION..........................................................................4 
 
1.1.  Objective of the guidance............................................................4 
1.2.  Background and scope of the guidance..........................................4 
1.3.  General principles......................................................................4 
 
2.  GUIDANCE.................................................................................5 
 
2.1 Repeat-dose (90-day) toxicity study test.............................................5 
1.1.1.  Purpose........................................................................5 
2.1.2.  Experimental design for a 90-day toxicity test 
2.1.2.1.Pathological examination........................................5 
 
      3.  REFERENCES...........................................................................5 
 
 
Page 3 
  Contains Non-Binding Recommendations 
REPEAT-DOSE (90-DAY) TOXICITY TESTING 
 
This guidance represents the agencys current thinking on establishing the safety of veterinary drug 
residues in human food.  It does not create or confer any rights for or on any person and does not 
operate to bind FDA or the public.  You can use an alternative approach if the approach satisfies the 
requirements of the applicable statute(s) and/or regulation(s).  If you want to discuss an alternative 
approach, contact the FDA staff responsible for implementing this guidance.  If you cannot identify 
the appropriate FDA staff, call the appropriate number listed on the title page of this guidance.  
 
 
1. INTRODUCTION 
 
1.1. Objective of the guidance 
 
A variety of toxicological evaluations are performed to establish the safety of veterinary 
drug residues in human food. The objective of this guidance is to establish 
recommendations for internationally harmonized 90-day repeat-dose testing.  
 
FDAs guidance documents, including this guidance, do not establish legally enforceable 
responsibilities.  Instead, guidances describe the Agencys current thinking on a topic and 
should be viewed only as recommendations, unless specific regulatory or statutory 
requirements are cited.  The use of the word should in Agency guidances means that 
something is suggested or recommended, but not required. 
 
 
1.2. Background and scope of the guidance 
 
The current guidance is one of a series of guidances developed to facilitate the mutual 
acceptance of safety data for the determination of acceptable daily intakes (ADIs) for 
veterinary drug residues in human food. This guidance was developed after 
consideration of the current practices for evaluating veterinary drug residues in human 
food in the European Union, Japan, United States, Australia, New Zealand, and Canada. 
 
Although this guidance recommends a framework for 90-day toxicity testing of veterinary 
drugs, it is important that the design of the tests remain flexible.  It is recommended that 
tests be tailored to adequately establish the dose-response and a no-observed adverse 
effect level (NOAEL) for toxicity following 90-day compound treatment.  
 
1.3. General principles 
 
Adequate toxicity testing should include an assessment of the effects of repeated 
exposure to a parent compound and/or metabolites. It should also ascertain a dose that 
does not produce toxicity. As with other types of toxicity testing it is recommended that 
available information on the compound be utilized in designing the test. Repeat-dose 
toxicity tests should be performed in sensitive/appropriate species. While species 
selection should take account of relevance to human metabolism, pharmacokinetics and 
pharmacodynamics, the generally accepted default species recommended are the rat 
and the dog. It is recommended that exposure begin early enough in life to encompass 
Page 4 
  Contains Non-Binding Recommendations 
the growth phase of the test animals. In general, the highest dose should be sufficient to 
produce toxicity. The data obtained from this test may be used to establish a NOAEL for 
a veterinary drug.  
 
 
 
2. GUIDANCE 
 
2.1. Repeat-dose (90-day) toxicity test  
 
2.1.1. Purpose 
 
It is recommended that repeat-dose (90-day) toxicity testing be performed in a rodent 
and a non-rodent species in order to (1) identify target organs and toxicological 
endpoints, (2) provide information that will help the setting of dose levels to be used in 
repeat-dose (chronic) toxicity testing, and (3) identify the most appropriate species for 
subsequent repeat-dose (chronic) toxicity testing. A NOAEL should be identified from the 
results of each repeat-dose (90-day) toxicity test. 
 
2.1.2. Experimental design for a 90-day toxicity test  
 
It is recommended that repeat-dose (90-day) toxicity tests be conducted in accordance 
with OECD Test Guidelines 408 Repeated Dose 90-day Oral Toxicity Study in 
Rodents1 and 409 Repeated Dose 90-day Oral Toxicity Study in Non-rodents.2 
 
2.1.2.1. Pathological examination  
 
It is recommended that gross necropsy and histopathological examination be performed 
in accordance with Organization for Economic Cooperation and Development 
(OECD)Test Guidelines 4081 and 4092 with the following exception: for non-rodents, 
histopathological evaluations should be made on a standardized set of tissues plus 
gross lesions from all animals in all groups. 
 
 
3. REFERENCES 
 
1.  OECD. 1998. Test Guideline 408. Repeated Dose 90-day Oral Toxicity Study in 
Rodents. In: OECD Guidelines for the Testing of Chemicals. Organisation for 
Economic Cooperation & Development, Paris.  
 
2.  OECD. 1998. Test Guideline 409. Repeated Dose 90-day Oral Toxicity Study in Non-
rodents. In: OECD Guidelines for the Testing of Chemicals.   Organisation for 
Economic Cooperation & Development, Paris.  
 
 
Page 5