Educational information, not medical advice — ask your doctor or midwife.
Untanto is a Kampo herbal formula used in Japan. The name means "decoction to warm the gallbladder". It is a ministry-approved Kampo formula, sold mostly as a granule extract.
It is given to people who feel jumpy, uneasy and sleep badly. Kampo doctors also use it for nausea, a heavy stomach and dizziness. In Kampo thinking, these signs point to "phlegm-damp" sitting in the chest and stomach.
The formula contains kanzo (licorice), which can raise blood pressure and lower potassium. It also contains hange (Pinellia ternata), which must be processed before use. Both facts are covered in the safety section below.
Tradition here is long and well documented. Tradition is not proof that a medicine works, and that applies to everything on this page. We could not find good human trials of Untanto itself.
The honest answer is that nobody has shown how Untanto works in people.
In Kampo terms, the formula is said to clear "phlegm-damp", settle the stomach and calm the mind. This is a traditional model of the body. It is not a test-tube finding and it is not a proven mechanism.
Some parts have been studied in the laboratory. In animal studies, extracts of Poria and sour jujube seed appear to have mild calming effects. Whether this happens in people taking the whole formula is not known.
One effect is well established in people, and it is a harm, not a benefit. Glycyrrhizin from licorice blocks an enzyme called 11-beta-HSD2. This makes the body hold on to salt and water and lose potassium.
Most people take Untanto as a dried granule extract. This is the standard form made by Japanese Kampo companies.
Other forms include: - Fine powder or tablets of the same extract - Loose raw herbs, boiled at home into a tea (a decoction) - Liquid extracts, less common outside Japan
Quality varies a lot between brands. Buy from a maker that tests its herbs and lists every ingredient. Ask a pharmacist or Kampo doctor if the label does not name the herbs.
Untanto is the Japanese name for a very old Chinese formula, Wen Dan Tang. Early versions appear in Tang era writings, and the better known recipe dates from the Song era.
The formula travelled to Japan with Chinese medical texts. Edo period Kampo doctors kept it and adjusted the herb amounts. It is still listed as an approved Kampo medicine in Japan today.
It is also used in Chinese and Korean practice, which gives it a wide traditional footing.
Stop taking it and call your doctor if your ankles or face swell, or you gain weight fast. The same goes for muscle weakness, cramps, numbness or a blood pressure rise.
Get urgent medical help for a racing or uneven heartbeat, severe muscle pain, or dark, cola-coloured urine. Yellow skin or eyes also needs same-day care.
See a doctor before starting if you have heart, kidney or liver problems. Also see a doctor if poor sleep, anxiety, nausea or dizziness lasts more than a few 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 Untanto 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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