Educational information, not medical advice — ask your doctor or midwife.
Seishitsukatanto is a Kampo herbal formula used in Japan. It is a Ministry-approved prescription medicine, made as granules by firms such as Tsumura. Its name means a decoction to clear dampness and transform phlegm.
It is given for a wet, rattling cough with thick phlegm. Kampo practitioners pick it for people who feel heavy, stuffy and damp in the chest. Some also use it for stiff, aching shoulders and arms in the same pattern.
The evidence verdict is short. We found no published human trials of this exact formula. It rests on long use in Kampo practice, and traditional use is not proof of effect.
The honest answer is that its action in the body has not been mapped.
In Kampo theory, the herbs dry "damp" and move "phlegm". That is a traditional idea, not a measured body process.
Single herbs in the blend have been studied in labs. In test tubes and animals, Pinellia and ginger extracts appear to calm cough and gut spasm. Whether that happens in people taking this formula is not known.
One effect is clear in people. Licorice (kanzo) can raise blood pressure and lower blood potassium. That is well documented and is the main reason for care with this product.
Almost all use is as a dry granule or fine powder.
The granules come in sachets. You stir the dose into warm water and drink it. Some people take the granules straight, with water.
A few pharmacies still make it as a hot decoction (a tea boiled from raw herbs). Tablets and capsules are much less common. Whatever the form, the Pinellia and Arisaema in it must be the processed, official grade.
The recipe is old. It is recorded in Ming-era Chinese medical writing and was later taken up by Japanese doctors.
In Japan it became one of the set formulas for wet, phlegm-heavy coughs. It now holds a licence as a Kampo prescription drug. That licence reflects traditional standing and safety rules, not proof from modern trials.
Some reactions to Seishitsukatanto need urgent care. Call your local emergency number or go to an emergency department straight away — do not wait to see whether it passes.
Stop the formula and get medical help the same day if you notice swelling of the ankles or face, sudden weight gain, strong muscle cramps, marked weakness, or a racing or irregular heartbeat. These can be signs that your potassium has fallen.
Stop and see a doctor if your skin or eyes turn yellow, your urine goes dark, or you feel very tired and sick. Also see a doctor for a new dry cough with fever and breathlessness.
Get emergency care if your mouth, tongue or throat swells, or if you struggle to breathe or swallow.
Any cough lasting more than three weeks, or a cough with blood, weight loss or chest pain, needs a doctor rather than a herbal medicine.
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 Seishitsukatanto 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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