Educational information, not medical advice — ask your doctor or midwife.
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Shoma is the dried root of a plant called Cimicifuga simplex. It is a single herb in Kampo, the old herb system of Japan. Its Latin name is Cimicifuga simplex, and it is also sold as Cimicifuga Rhizome.
It is used at the very start of a fever or a chill. Kampo says Shoma brings out sweat and "raises yang". In plain words, it is meant to lift low energy and push a new illness out through the skin.
Older texts also use it for sore throat, mouth sores, skin rashes and piles (swollen veins around the back passage). Now the verdict on proof: Shoma has a long record of use, but almost no human trials back it up. Long use is not proof that a herb works, and this page keeps the two apart.
Honest answer first. No one has shown how Shoma works in a sick person.
Lab tests on Cimicifuga roots find plant acids and soap-like compounds. In test tubes and in animals, some of these damp down swelling and slow the growth of germs. That is a long way from proof in people.
Kampo explains it in its own way. It says the root opens the surface of the body, brings out sweat, and lifts qi (the flow of life energy) that has sunk. This is a way of thinking about the body, not a measured drug effect.
The sweating effect is the one thing users report often. Even that has not been checked in a proper human trial of Shoma on its own.
Shoma is sold as a dried, sliced root. Most people meet it inside a ready-made Kampo formula rather than on its own.
The usual forms are dried root slices for simmering into a tea, and granules or powder in single-dose packets. Packets are the standard form in Japan. Tablets and capsules of powdered root are also sold.
Check the label for the Latin name Cimicifuga simplex. Some products use black cohosh (Cimicifuga racemosa), which is a different plant used for a different purpose.
Shoma is an old herb. The root is listed in the first Chinese herb classic, written about 2,000 years ago, where it is called sheng ma. Japanese doctors later took it into Kampo.
It is still an official crude drug in Japan. It appears in formulas such as Shomakakkonto, used for the first day of a fever with a rash, and Otsujito, used for piles.
Korean and Chinese herb systems use closely related Cimicifuga roots in much the same way. That shared use across traditions is why its traditional standing is strong, even though its test record is not.
See a doctor if your fever lasts more than three days, or goes above 39C (102F). Get help the same day for a stiff neck, a rash that does not fade under pressure, chest pain, trouble breathing or confusion.
Stop the herb and call a doctor if your skin or eyes turn yellow, your urine turns dark, or you get pain under your right ribs. These can be signs of liver trouble.
Also get checked if you feel faint, cannot keep fluids down, or if a young child or an older adult is not picking up.
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 Shoma 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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