I've previously showed you how to find ibuprofen in Japan, but what about acetaminophen? Otherwise known as Tylenol. Though Tylenol itself is a bit more difficult to find in Japan than ibuprofen (I can't find it in my local drugstore but I can find it in the drugstore in the closest major train station in my area). You can also find it online quite easily. Though, keep in mind that some other brands of medicine in Japan also contain acetaminophen, but many of those brands also contain caffeine (カフェイン), occasionally aspirin (アスピリン), and some other active ingredients. Yeah, probably not what you want, necessarily.
First things first: acetaminophen in Japanese is アセトアミノフェン.
And, Tylenol is タイレノール.
You can buy it online via Kenko.com, an e-drugstore I reviewed in an earlier post, or, check out your local drugstore/daily goods store (though I think you'll probably have better luck finding it in stores nearer larger train stations or larger stores in general).
You might be thinking that the amount of acetaminophen is nothing compared to Western-bought Tylenol, but I can assure you, the box I have says each pill holds 300 mg, while Tylenol's English website states their regular strength pills have 325 mg of acetaminophen in each tablet. Yes, it's a 25 mg difference, but most of you will probably agree that's practically the same.
So there you go, if you need acetaminophen, for whatever reason, now you're set.