noun
antacid; anti-acid preparation
Medical term for a substance that neutralizes stomach acid, such as over-the-counter tablets or liquids.
胃が痛いので、制酸剤を飲んだ。
My stomach hurt, so I took an antacid.
胃薬 is a broader term for stomach medicine, while 制酸剤 specifically refers to antacids that neutralize acid.
Compound of 制 (control), 酸 (acid), and 剤 (preparation, medicine).