Tatsuomi Matsuoka et al / Int. J. of Res. in Pharmacology &Pharmacotherapeutics Vol-12(3) 2023 [153-156]

International Journal of Research in Pharmacology& Pharmacotherapeutics (IJRPP)

IJRPP |Volume 12 | Issue 3 | July - Sept – 2023
www.ijrpp.com
Case Study

ISSN:2278-2648

Medical research

Oral intake of a widely available gastrointestinal OTC medicine ‘Seirogan’ is effective
for gastric anisakiasis (Anisakis food poisoning)
Takuya Matsuoka1, Tatsuomi Matsuoka2*1

Kyoshin Co. Ltd., Takarazuka 665-0044, JapanEmeritus professor, Department of Biological Science, Faculty of Science and Technology, Kochi University, Kochi
780-8520, Japan.
2

Corresponding author: Tatsuomi Matsuoka
Published on: 08.08.2023

ABSTRACT
Gastric food poisoning due to anisakid nematodes (gastric anisakiasis) is characterized by severe stomach pain caused by theconsumption of raw fish that harbors anisakid nematodes. The only effective treatment that is currently available is the endoscopic
removal of nematodes penetrating the stomach wall. An in vitro study showed that the widely available over-the-counter (OTC)
gastrointestinal medicine 'Seirogan' containing wood creosote kills Anisakis larvae. In addition, two cases in which the oral intakeof Seirogan alleviated gastric anisakiasis symptoms have been reported. Herein, we analyzed 56 statements regarding Seirogan'sefficacy against gastric anisakiasis posted on social networking sites (SNSs) in Japan. There were 33 statements (59%) that Seirogan
was effective in significantly alleviating or eliminating symptoms of gastric anisakiasis, 13 comments (23%) stating that it had aslight effect, and 10 comments (18%) stating that there was no effect. These results indicate that in many cases, an oral intake of
Seirogan is effective as first aid to remove or alleviate severe stomach pain due to gastric anisakiasis.

Keywords: Anisakis, gastric anisakiasis, Seirogan, wood creosote.

physicians who can perform the necessary endoscopy for
gastric anisakiasis symptoms are often not available in the
middle of the night. Therefore, the development of an oral
therapeutic medicine for gastric anisakiasis is desired.
Ten years ago, an in vitro experiment showed that a widely
available over-the-counter (OTC) medicine called 'Seirogan'containing wood creosote [4], which is a traditional
gastrointestinal medicine that has been used for >100 years inJapan, quickly suppressed the motility of Anisakis larvae [5].
More recent in vitro experiments demonstrated that theSeirogan components killed the majority of Anisakis larvae at
the concentration of three pills (i.e., the single dose)/30 ml of
0.01 M HCl (corresponding to a volume of fasting gastricjuice and HCl concentration contained in it), and the killed
nematodes were digested in the solution that mimicked

INTRODUCTION
Gastric food poisoning due to anisakid nematodes (gastricanisakiasis) is characterized by unbearable stomach pain due
to a penetration of anisakid nematodes into the stomach wall.
Gastric anisakiasis is caused by eating raw fish such as'sashimi' that harbors nematodes such as Anisakis simplex(see Fig. 1), A. pegreffii and Pseudoterranova decipiens [1,2].
The only effective treatment that is currently available forgastric anisakiasis is the endoscopic removal of nematodes
that have penetrated the stomach wall [3]. Severe stomach
pain due to gastric anisakiasis occurs within several hours to12 hr after eating raw fish harboring anisakid nematodes. The
symptoms usually appear in the middle of the night, since raw
fish is usually eaten for dinner. Emergency department

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Tatsuomi Matsuoka et al / Int. J. of Res. in Pharmacology &Pharmacotherapeutics Vol-12(3) 2023 [153-156]
gastric juice (0.01 M HCl containing pepsin) [6]. These invitro results suggested that Anisakis larvae attached to thestomach wall may be killed by this single dose if three pills ofSeirogan are completely dissolved in 30 ml of gastric fluid in
the fasted state.
Actually, two cases in which an oral intake of Seirogan
alleviated patients' gastric anisakiasis symptoms have beenreported [5]. In the present study, we examined the efficacyof the oral intake of Seirogan for gastric anisakiasis(including self-diagnosis) based on statements posted onsocial networking sites (SNSs) in Japan.

posted on SNSs in Japan between April 4, 2015 and June 13,2023. Many of the posts were personal comments on yahoonews and other scientific news regarding gastric anisakiasis.

RESULTS AND DISCUSSION
Figure 2 depicts the efficacy of the oral intake of Seiroganon gastric anisakiasis based on the statements posted on theSNSs. Thirty-three (59%) of the posters on the SNSs statedthat Seirogan was effective in significantly alleviating oreliminating severe stomach pain, while 13 (23%) stated that
it was slightly effective, and 10 (18%) stated that it was noteffective at all. In many cases, the posters self-diagnosed
gastric anisakiasis because severe gastric pain appeared
within about 12 hr after they had consumed raw fish.

METHODS
We analyzed 56 statements (all we could find except for a few
poorly written posts) on the "efficacy of oral intake of
Seirogan on gastric anisakiasis (including self-diagnosis)"

Fig 1: Living larvae of Anisakis simplex.

Fig 2: Effects of the oral intake of Seirogan on gastric anisakiasis.

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third, but the poster's stomach hurt for 3 days.

Case reports
The following are representative cases for each category of
Seirogan's effectiveness for gastric anisakiasis symptoms(effective, slightly effective, no effect) in the pie chart shownin Fig 2. These case reports are excerpts and/or summaries
of personal comments on yahoo news (already deleated) andother scientific news regarding gastric anisakiasis (URLslisted below).
https://news.yahoo.co.jp/articles/047619a53f052cf726dd3dd4314a29304c79faa0;
https://news.yahoo.co.jp/articles/4be8b19b757d56e9d4d4ca
ae73183eab3004dae1;
https://news.yahoo.co.jp/articles/bfaf2b5d87a2c8c09c9057b
4881ac719179 b6ec1;
https://nazology.net/archives/95980/2;
https://moyarin.com/12547.html

Seirogan had no effectCases in which the posters' symptoms was not relieved at all
after the oral intake of Seirogan.

Case 1This poster was attacked by an anisakid nematode hidden in
raw squid. He took Seirogan but it did not work to relieve
symptom of anisakiasis. He then had the nematode removed
via endoscopy at a hospital.

Case 2This poster had such terrible abdominal pain that (s)he could
not move and her (his) saliva overflowed. (S)he took
Seirogan and other stomach medicine but they were noteffective in relieving symptom of anisakiasis. (S)he sufferedfrom pain for more than 4 days.

Seirogan was effective
Cases in which the posters' symptoms relieved significantlyor disappeared completely after oral intake of Seirogan.

In many of the SNS posters' statements, the dosage of
Seirogan taken was not described accurately. Some people
took more than the maximum dosage. Many of the posters
who reported no effect of Seirogan and those who
experienced a slight effect received a diagnosis of gastricanisakiasis at a hospital. On the other hand, most of theposters whose symptoms improved dramatically after taking
Seirogan did not seek medical attention, and thus there is no
medical evidence that these posters had gastric anisakiasis;
rather, they were self-diagnosed because they had a severe
stomachache after they ate raw fish.
Our survey identified a 41% rate of cases in which Seirogan
was not sufficiently effective. The following are possible
causes of inadequate efficacy of Seirogan.
(1) The Seirogan concentration in the stomach may not reachthe lethal concentration to kill almost all anisakid nematodes.
In vitro experiments [6] showed that 13.3% of nematodes
treated with Seirogan solution (1 pill/10 ml) were still moving
24 hr later, and 8.3% of nematodes whose motility had
completely ceased at 24 hr were still alive (not stained withtrypan blue). Thus, about 20% of Seirogan-treated nematodes
remained alive. In addition, the Seirogan concentration in thestomach will not reach lethal concentrations if the Seirogan
pills are not crushed completely, or when the Seirogan istaken with a large amount of water.
(2) Anisakid nematode penetrates the stomach wall so deeplythat only the the posterior portion of the nematode body isexposed to the Seirogan solution. In this case, it is difficult tokill the anterior portion penetrating the stomach wall. The invitro experiment showed that the posterior portion ofnematodes that were dipped in Seirogan solution stopped
moving soon but the remaining anterior portion continued toactively move [6], supporting this speculation.
(3) Anisakid nematodes penetrate the upper part of thestomach, making it difficult for it to be exposed to Seirogansolution.
It is possible that anisakid nematodes that are weakened anddetached from stomach wall by exposure to Seirogan solution
migrate to the intestine and reactivated nematodes may
penetrate the intestinal wall. In this case, the nematodes can
not be removed with the use of an endoscope. In the present
survey, there was no such report. Further clinical studies

Case 1After eating raw fish (sashimi), this poster had periodic
severe stomach pain in the middle of the night. However,(s)he hesitated to call an ambulance because it was in themiddle of the night. (S)he got information on a SNS that
Seirogan was effective for gastric anisakiasis, and reported
that after taking the Seirogan, the pain went away within afew minutes.

Case 2After eating raw fish (bonito sashimi), this poster sufferedfrom severe stomach pain in the middle of the night. Aftertaking Seirogan, (s)he had almost no pain until they went to
the hospital the next day. The examination at the hospital
identified an anisakid nematode that had stopped moving, andit was easily removed.

Case 3After eating raw fish (sashimi), this poster had such severe
abdominal pain that he could not stand up and walk. After hetook Seirogan, the pain subsided within an hour or so and hebecame able to walk. When he was examined at a hospital,
the anisakid nematode had already been expelled.

Seirogan was slightly effective
Cases in which the posters' symptoms relieved somewhat
after the oral intake of Seirogan.

Case 1
Seirogan was effective in delaying the cycle of pain andrelieving it to some extent. This poster was able to tolerate thepain by taking Seirogan for one day, but on the second day,(s)he went to the hospital and had a nematode removed withendoscope.

Case 2
Seirogan reduced the poster's stomachache to about one-155

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should be conducted to determine whether such risks may
arise, and to establish the safe and effective dosage and usageof Seirogan to kill the majority of or all anisakid nematodes
present in the stomach.

CONCLUSION
The results of the present survey revealed that in many cases, an oral intake of Seirogan was effective as first aid to remove oralleviate severe stomach pain due to gastric anisakiasis.

REFERENCES
1.
2.
3.
4.
5.

6.

Sakanari JA, McKerrow JH. Anisakiasis. Clin Microbiol Rev. 1989;2(3):278-84. doi: 10.1128/CMR.2.3.278, PMID
2670191.
Aibinu IE, Smooker PM, Lopata AL. Anisakis nematodes in fish and shellfish- from infection to allergies. Int J Parasitol
Parasites Wildl. 2019;9:384-93. doi: 10.1016/j.ijppaw.2019.04.007, PMID 31338296.
Pravettoni V, Primavesi L, Piantanida M. Anisakis simplex: current knowledge. Eur Ann Allergy Clin Immunol.
2012;44(4):150-6. PMID 23092000.
Ogata N, Tagishi H, Tsuji M. Inhibition of acetylcholinesterase by wood creosote and simple phenolic compounds. Chem
Pharm Bull (Tokyo). 2020;68(12):1193-200. doi: 10.1248/cpb.c20-00583, PMID 33268651.
Sekimoto M, Nagano H, Fujiwara Y, Watanabe T, Katsu K, Doki Y, et al. Two cases of gastric anisakiasis for which oral
administration of a medicine containing wood creosote (Seirogan) was effective. Hepato-Gastroenterology.
2011;58(109):1252-4. doi: 10.5754/hge11052. PMID 21937389.
Matsuoka K, Matsuoka T. Over-the-counter medicine (Seirogan) containing wood creosote kills Anisakis larvae. Open J
Pharmacol Pharmacother. 2021;6(1):9-12. doi: 10.17352/ojpp.000017.

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