Educational information, not medical advice — ask your doctor or midwife.
Anchusan is a Japanese Kampo herbal formula taken for long-running stomach trouble. It is used for chronic gastritis (long-term soreness of the stomach lining), gastric pain (stomach pain) and hyperacidity (too much stomach acid). In Kampo it is given as a single drug — one formula on its own, not combined with other formulas.
The name is often translated as "Centre-Calming Powder", because it aims to settle the middle of the body, meaning the stomach. Practitioners match it to thin, cold-type patients: slender people who feel the cold easily and whose stomach pain eases with warmth and worsens when they are cold or hungry.
Evidence verdict: Anchusan has a long, steady record in Kampo practice, but we could not find good-quality human trials comparing it with a dummy treatment. Long traditional use is not proof that a remedy works, and this document reports those two things on separate lines.
One practical point before you read on: Anchusan contains licorice root, so it is not a "routine" everyday herb. See the safety section below.
The honest answer is that nobody has shown clearly how Anchusan works in people. The ideas below come from what each ingredient does in the laboratory or in animals.
Oyster shell is mostly calcium carbonate, the same chemical used in simple antacids, so it may soak up some stomach acid. Licorice and its compound glycyrrhizin appear to soothe irritated stomach lining in animal studies. Corydalis contains alkaloids studied for pain-dulling effects.
Cinnamon, clove, fennel and amomum are warming, aromatic herbs. In Kampo terms they are said to warm a cold stomach and move stalled digestion. That is a traditional description of a pattern, not a measured biological effect.
The usual form in Japan is a dried water-extract granule or fine powder, sold in single-dose sachets. Both pharmacy (over-the-counter) and prescription versions exist.
You may also see tablets or capsules of the same extract, made for people who dislike the taste. Traditional practitioners sometimes prepare it as a powder taken with warm water.
Strength differs between brands. Always follow the dose printed on the pack you actually have, not a dose copied from another product.
Anchusan comes from the Song dynasty Chinese formulary Taiping Huimin Heji Jufang, compiled around the 12th century. It was carried into Japan and became a standard Kampo stomach formula.
In modern Japan it is an approved Kampo preparation, widely stocked in pharmacies for gastritis and acid stomach. That makes it a long-standing staple of Kampo practice.
See a doctor promptly if your ankles, hands or face swell, if your muscles feel weak or keep cramping, if you feel unusually thirsty or tired, or if your blood pressure climbs.
Get urgent medical help if you have chest pain, a racing or irregular heartbeat, severe muscle pain with dark urine, or if you vomit blood or pass black, tarry stools.
Also get checked, rather than carrying on with Anchusan, if you have stomach pain with weight loss, trouble swallowing, repeated vomiting, or if your symptoms have not improved after four weeks.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
The published evidence for Anchusan is weak or absent. That usually means no controlled trial has tested it, not that a trial found it ineffective — the two are different, and we grade only what has been published.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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