What is Anchusan?

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.

How does Anchusan work?

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.

What forms does Anchusan come in?

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.

Where it comes from:

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.

What does Anchusan help with?

• Chronic gastritis (long-term soreness of the stomach lining): This is the classic Kampo use for Anchusan, and it is the reason most Japanese pharmacies stock it. Practitioners choose it for slender, cold-feeling people with a dull, gnawing ache. High-quality human trials testing it against a dummy treatment are not available to us.
• Gastric pain (stomach pain): Tradition matches Anchusan to pain that eases when you apply warmth, drink something warm or eat, and worsens with cold or an empty stomach. Corydalis in the mix has been studied for pain-dulling effects in animals. Whether that translates into real relief in people has not been shown in solid trials.
• Hyperacidity (too much stomach acid) and heartburn: The oyster shell in the formula is calcium carbonate, the same acid-neutralising chemical found in plain antacids, so some short-term easing of burning is plausible. Standard antacids and acid-blocking medicines have far stronger trial support for this job. Anchusan is not a substitute for treatment your doctor has prescribed.
• Functional dyspepsia (ongoing indigestion with no disease found on tests): Kampo doctors use Anchusan for this pattern when the person is thin and cold-natured, and other Kampo formulas are chosen for other body types. Published Japanese clinical work on Kampo dyspepsia treatment focuses mainly on a different formula, rikkunshito, not Anchusan. Direct trial evidence for Anchusan here is thin.

Which foods are rich in Anchusan?

1. Licorice sweets and licorice root tea: they add to the same licorice load and raise the risk of swelling and low potassium
2. Cinnamon: a kitchen spice and one of the formula's ingredients, though food amounts are small
3. Fennel seed: used as a digestive tea in many kitchens, and one of the ingredients
4. Cloves: a common baking spice, also in the formula

Practical Tips:

Anchusan is not a nutrient found in food; the point that matters is to avoid extra licorice from sweets or tea while you take it.

What are the side effects of Anchusan?

• Swollen ankles, hands or face (fluid retention)
• Rising blood pressure
• Low potassium, which can cause muscle weakness, cramps or an odd heartbeat
• Unusual tiredness or heavy legs
• Nausea or stomach upset
• Skin rash or itching (allergic reaction)
• Rarely, severe muscle pain with dark urine (a sign of muscle breakdown)

Good to know:

Most people who take Anchusan for a short period have no trouble with it. The concern that lifts it above an everyday herb is the licorice.

Regular or long licorice use can cause pseudoaldosteronism (a licorice reaction that lowers blood potassium, raises blood pressure and causes swelling). This is a recognised and reported problem with licorice-containing Kampo formulas in Japan, not a theoretical worry.

The risk goes up with higher doses, longer use, older age, and if you take water tablets or steroids. Swelling, cramps, weakness or a racing heart are the warning signs to act on.

How much Anchusan should you take?

• Recommended daily: A common adult dose of the standard Japanese extract granule is about 7.5 g per day, split into two or three doses. That usually supplies roughly 1 g of licorice root per day. Brands differ, so the number on your pack is the number to follow. Do not take a second licorice-containing product on top of it without medical advice. Doses for children, older adults and people with heart, liver or kidney problems should be set by a doctor or pharmacist, not guessed at home.
• Best time of day: Usually taken two or three times a day, spaced through the day, before or between meals. Taking it before food is the traditional pattern.
• With or without food: Traditionally taken on an empty stomach — before meals or between them — with warm water. If it makes you feel queasy, taking it just after food is acceptable.
• Time to effect: Any easing of burning or discomfort may be felt within a few days. Traditional practice expects a fuller picture after two to four weeks.
• How long to take it: Treat it as a short trial, not a daily habit. Give it two to four weeks, then judge honestly whether your symptoms are better. If nothing has changed by four weeks, stop and get your stomach checked properly. If you do want to continue for months, your doctor should check your blood pressure and blood potassium level, because of the licorice.