Aspirin in Japan: Bufferin A and Bayer Aspirin
Aspirin: how it is named on Japanese boxes, the 2 products in this database that contain it, how their doses compare with US labels, and the rules for bringing it into Japan and taking it home. On 3 October 2026, PMDA's search of OTC package inserts returned 43 products containing aspirin (including aspirin aluminium).
What it is called on Japanese boxes
How aspirin is written on Japanese boxes, with the official English name from the JAN database or the Japanese Pharmacopoeia.
| Official English name | Name on Japanese boxes | Listed in |
|---|---|---|
| Aspirin | アスピリン | JAN; also Acetylsalicylic Acid |
Aspirin in Japanese products
The amount of aspirin per dose and per day, as each package insert sets it.
On 3 October 2026, PMDA's search of OTC package inserts returned 43 products containing aspirin (including aspirin aluminium).
| Product | Amount | Most a day for adults | Class on the box |
|---|---|---|---|
| Bufferin A | 660 mg per dose of 2 tablets | 1,320 mg (2 doses a day) | 第②類医薬品 |
| Bayer Aspirin (Japan) | 500 mg per dose of 1 tablet | 1,500 mg (3 doses a day) | 第②類医薬品 |
Most a day for adults, by the package insert (mg)
Each package insert sets its own dose. Follow the directions and dosage on the box you buy.
Japanese doses and US labels
US doses come from the OTC labels on DailyMed.
| Product | Where | Amount | Most a day for adults |
|---|---|---|---|
| Bufferin A | Japan, package insert | 660 mg per dose of 2 tablets | 1,320 mg (2 doses a day) |
| Bayer Aspirin (Japan) | Japan, package insert | 500 mg per dose of 1 tablet | 1,500 mg (3 doses a day) |
| Bayer Genuine Aspirin | US, OTC label | 325 mg per tablet | 3,900 mg (12 tablets in 24 hours) |
| Bayer Aspirin Extra Strength Caplets | US, OTC label | 500 mg per caplet | 4,000 mg (8 caplets in 24 hours) |
Follow the directions and dosage exactly.That is the wording of the Japanese package inserts. The table lines up what each product's own directions say; it is not a guide to how much to take.
The directions on the US labels, as printed
Bringing it into Japan
Medicine with aspirin that you bring for your own use counts towards Japan's supply limits for medicine.
Taking it home
Frequently asked questions
Is aspirin sold over the counter in Japan?
On 3 October 2026, PMDA's search of OTC package inserts returned 43 products containing aspirin (including aspirin aluminium). In this database: Bufferin A, Bayer Aspirin (Japan).
How much Aspirin is in Bufferin A?
660 mg per dose of 2 tablets, and at most 1,320 mg (2 doses a day) by its package insert.
How does Bufferin A compare with Bayer Genuine Aspirin?
Bufferin A: 660 mg per dose of 2 tablets, at most 1,320 mg (2 doses a day) (Japanese package insert). Bayer Genuine Aspirin: 325 mg per tablet, at most 3,900 mg (12 tablets in 24 hours) (US label). Each product's directions apply only to that product.
Related items
PMDA package insert search (Japanese)
Sources for this page
- PMDA (Pharmaceuticals and Medical Devices Agency) OTC and guidance-required drug package insert search (一般用医薬品・要指導医薬品 添付文書等情報検索)checked October 3, 2026
- National Institute of Health Sciences Japanese Accepted Names for Pharmaceuticals (JAN) databasechecked October 3, 2026
- PMDA (Pharmaceuticals and Medical Devices Agency) バファリンA: package insert (添付文書)checked October 3, 2026
- PMDA (Pharmaceuticals and Medical Devices Agency) バイエルアスピリン: package insert (添付文書)checked October 3, 2026
- DailyMed (US National Library of Medicine) Bayer Aspirin: Bayer Genuine Aspirin labelchecked October 3, 2026
- DailyMed (US National Library of Medicine) Bayer Aspirin: Bayer Aspirin Extra Strength Caplets labelchecked October 3, 2026
Compiled by Japan Japan !! · Updated October 3, 2026