Best Japanese Stomach Medicines 2026: 7 Picks + Box Words

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December and January in Japan mean big meals: year-end parties, 忘年会 bōnenkai, Christmas, then the New Year feast. If your stomach feels heavy the next morning, drugstores such as Matsumoto Kiyoshi, Sundrug or Don Quijote have a whole shelf of 胃腸薬, ichōyaku, stomach medicines, almost all labelled only in Japanese.

This guide is only about stomach medicines. It explains the four main types, the box words, what to check, then 7 products sold in Japan with prices checked on 12 November 2026. There is no ranking. Doses, ages and warnings come from the package inserts, 添付文書, published by PMDA, Japan’s medicines agency. This is not medical advice: read the label, ask the pharmacist, 薬剤師 yakuzaishi, if unsure.

For other medicines, see our Japanese drugstore medicine guide. For how drugstores work in general, see our Japan drugstore shopping guide. Planning the New Year meal? Our osechi guide explains how to order it.

Which type for which symptom

Japanese stomach medicines fall into four broad groups. Most famous brands are combination medicines: one dose holds an antacid, digestive enzymes, often herbal powders too.

※ Types summarised from each product’s package insert on PMDA. Some combination medicines also contain a probiotic, for example 第一三共胃腸薬プラス.

What the risk class on the box means

Every Japanese over-the-counter medicine has a risk class printed on the box. The Japan Self-Medication Industry, 日本OTC医薬品協会, explains them like this:

• 第1類医薬品, class 1: needs special care. Only a pharmacist can sell it, with a written explanation. No pharmacist on duty means you cannot buy it.
• 第2類医薬品, class 2: a pharmacist or a registered seller, 登録販売者 tōroku hanbaisha, can sell it. 指定第2類 marks class 2 products that need extra care.
• 第3類医薬品, class 3: lower risk.

Most stomach medicines are class 2: take one from the shelf, then ask questions when you pay.

Read the box, check before you buy

The symptoms on the box come from the official list of uses, 効能・効果. The words you will see most often:

※ Words taken from the package inserts on PMDA. The meaning of 食間 is from the 太田胃散 insert.

7 stomach medicines to look for

Four combination medicines, one kampo medicine, one H2 blocker, then a probiotic. Ages, doses and warnings are from each product’s package insert.

1. 太田胃散S (Ohta’s Isan S)

A classic brand sold in a round tin with a small spoon; the current powder is labelled 太田胃散S. It mixes seven herbal powders, such as cinnamon, fennel, clove, with antacids plus a digestive enzyme. Its uses include 胸やけ, 胃もたれ, 食べ過ぎ, 消化不良, 胃痛. Adults take 1.3 g, about one level spoon. Not for people on dialysis, 透析, nor for long-term use.

2. キャベジンコーワαプラス (Cabagin Kowa α Plus)

Cabagin is built around MMSC, メチルメチオニンスルホニウムクロリド, a compound first found in cabbage. The tablets also contain antacids, digestive enzymes, herbs, plus ロートエキス, scopolia extract. So the insert says: not with stomach cramp medicines, not while breast-feeding. Ask first if you are pregnant, elderly, have glaucoma, 緑内障, or difficulty passing urine. Shops now mainly sell αプラス; older boxes say α.

3. 第一三共胃腸薬プラス 細粒 / 錠剤 (Daiichi Sankyo Ichoyaku Plus)

From the maker of ガスター10. It combines digestive enzymes, antacids, herbs, a stomach-lining ingredient, plus a lactic acid bacterium, so its uses cover もたれ, 胸やけ, as well as 整腸, regulating the bowels. The two forms have different age limits: 細粒, fine granules, from age 3 in small doses; 錠剤, tablets, from 11.

4. パンシロン01プラス (Pansiron 01 Plus)

Rohto says 01プラス has 13 active ingredients, the most in its Pansiron range, and aims it at a heavy stomach after overeating. They include antacids, enzymes, stomach-lining ingredients, herbs, plus ロートエキス, so like Cabagin it is not for use with stomach cramp medicines, nor while breast-feeding.

5. 大正漢方胃腸薬 (Taisho Kampo Ichoyaku)

A kampo medicine combining two traditional formulas: 安中散, anchūsan, plus an extract of 芍薬甘草湯, shakuyaku kanzō tō. Its uses include 胃のもたれ, 胃痛, 胸やけ, 胃炎. Unlike most others here, you take it before meals, 食前, or between meals. The insert warns of rare liver problems, with signs such as fever, yellow skin, dark urine.

6. ガスター10 (Gaster 10)

Gaster 10 contains famotidine 10 mg, an H2 blocker that reduces stomach acid. Uses: 胃痛, もたれ, 胸やけ, むかつき. As a 第1類医薬品, a pharmacist must explain it before you buy. Take one when symptoms appear, at least 8 hours apart. Stop once you feel better.

7. 新ビオフェルミンS錠 (Shin Biofermin S)

A well-known probiotic, 整腸剤, in a different category: 指定医薬部外品, a quasi-drug. The tablets contain three kinds of lactic acid bacteria. The box lists 整腸, 軟便, 便秘, 腹部膨満感, plus upset stomach from travel, a change of surroundings. It does not treat heartburn.

Also on shelves: Lion’s スクラート胃腸薬, ¥769 for 36 tablets, plus Rohto’s パンシロンキュアSP for acid heartburn, ¥792 for 30 tablets, both class 2. We did not check their inserts.

All 7 compared

※ Prices as shown on Yodobashi.com, with tax. Drugstore prices differ. Ages, forms, classes are from the package inserts on PMDA.

Buying, tax-free, when to see a doctor

How to ask at the counter

Look for the shelf marked 胃腸薬. Staff badges say 薬剤師, pharmacist; 登録販売者, registered seller. Useful phrases:

• 「胃もたれに効く薬はありますか？」 I-motare ni kiku kusuri wa arimasu ka? Do you have medicine for a heavy stomach?
• 「胸やけがします。」 Muneyake ga shimasu. I have heartburn.
• 「ほかの薬を飲んでいます。」 Hoka no kusuri o nonde imasu. I am taking other medicine.

More tips are in our drugstore shopping guide.

Can I buy stomach medicine tax-free?

Since 1 November 2026, Japan uses a refund method. According to the Japan Tourism Agency, 観光庁, you pay the full price with tax, then get the tax back after customs checks the goods when you leave, within 90 days. You need to spend at least ¥5,000 before tax in one shop on one day, then carry all the goods yourself at departure.

The agency says that if you use up consumables such as food, drinks, cosmetics in Japan, you cannot get the refund. Medicines are not named there, so keep tax-free medicine unopened. Read more in our Japan tax-free shopping guide.

Taking medicine home

Rules for bringing medicine into your own country are set by that country. Check them before you fly, keep medicine in its original box, and keep the insert.

When to stop, see a doctor

The inserts give clear limits. Cabagin, Ohta’s Isan: stop, ask for advice if there is no change after about 2 weeks. ガスター10: after 3 days, never more than 2 weeks in a row. Taisho Kampo: after about one month. The ガスター10 insert also asks people with continuing belly pain, or unexplained weight loss, to talk to a doctor, pharmacist first. If pain is strong, comes back, or worries you, see a doctor. See also our OTC medicine guide.

Frequently asked questions

Do I need a pharmacist to buy Japanese stomach medicine?

Only for 第1類 products such as ガスター10. Class 2 products such as 太田胃散S, キャベジン, 第一三共胃腸薬, パンシロン can be sold by a registered seller.

Which one is for heartburn?

Most combination medicines list 胸やけ because they contain antacids. ガスター10 also lists it, but only a pharmacist can sell it.

Which one is for a heavy stomach after a big meal?

Look for 胃もたれ, 食べすぎ, 消化不良 on the box. 太田胃散S, キャベジンコーワαプラス, 第一三共胃腸薬プラス, パンシロン01プラス all list these.

Can children take Japanese stomach medicine?

Some can, at a lower dose, from age 3, 5 or 8 depending on the product. ガスター10 is not for under-15s. Ask a pharmacist.

Is Biofermin a stomach medicine?

新ビオフェルミンS is a probiotic for the bowels, a 指定医薬部外品. It is not for heartburn.

Can I take stomach medicine while pregnant?

ガスター10 must not be taken during pregnancy. For the others, the inserts say to ask a doctor, pharmacist first. Please do that.

The short version

For a heavy stomach or heartburn after a big meal, most people in Japan buy a class 2 combination medicine: 太田胃散S, キャベジンコーワαプラス, 第一三共胃腸薬プラス or パンシロン01プラス, about ¥900 to ¥1,700. For a herbal option there is 大正漢方胃腸薬. ガスター10, an H2 blocker, is sold only by a pharmacist, for ages 15 to 79. 新ビオフェルミンS is a probiotic for the bowels. Read the age table, do not mix stomach medicines, see a doctor if symptoms continue. Enjoy the holiday food, and see our osechi guide for the New Year feast.

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