Educational information, not medical advice — ask your doctor or midwife.
Atractylodes lancea is a root used in traditional Chinese medicine, best known as cang zhu. The dried rootstock is sliced and boiled into a tea, or ground and put into pills and capsules. Old texts used it for bloating, poor appetite and loose stools.
The plant is in the daisy family. It grows in China, and related crops are grown in Japan and Korea. Most of what you can buy is the dried root, often blended with other herbs rather than sold alone.
Here is the evidence verdict in one line: human trials of this root on its own are few, small and weak, so no health claim is settled. Long traditional use tells you the plant has a history. It does not tell you that it works, and it does not tell you that it is safe.
Two name mix-ups matter. Atractylodes macrocephala (bai zhu) is a different herb with different traditional uses. Atractylis gummifera is a different plant altogether, and it is poisonous to the liver.
The honest answer is that no one has shown how this root acts in the human body.
Almost all of the research sits in test tubes and in animals. In lab tests, the root's oil appears to damp down some signals linked to swelling and redness. In rodents, extracts have changed how fast the stomach empties, with mixed results between studies.
β-eudesmol, a main part of the oil, has acted on nerve and muscle signalling in laboratory work. Whether that happens in a person drinking a cup of the tea is not known.
Some animal work has reported lower blood sugar after extracts were given. This has not been confirmed in people. It is still worth knowing if you take diabetes medicine.
In traditional terms, healers said cang zhu "dried damp" in the gut and the joints. That is an old way of describing the body. It is not a mechanism that modern testing has confirmed.
You will most often meet this root as dried slices sold for making tea.
Common forms: - dried sliced root, boiled in water as a decoction (a strong tea) - powdered root, loose or in capsules - granules or instant powders made from a water extract - liquid tinctures made with alcohol - an ingredient in set formulas, such as Japanese Kampo mixes - the steam-distilled essential oil, used for scent and fumigation
In traditional practice the root is rarely used alone. It usually sits inside a multi-herb formula chosen by a practitioner.
The essential oil is a different thing from the tea. It is very concentrated and is not a drink. Swallowing it is not a traditional use and is not safe to try.
Quality varies widely between sellers. Look for a product that names the plant in full, in Latin, and names the plant part used.
Cang zhu has a long record in Chinese herbal writing. Early texts listed a herb called "zhu", and later authors split it into two: cang zhu and bai zhu. By the Song period the two were treated as separate medicines with separate roles.
Healers classed it as a warm, drying herb. They gave it for a heavy, bloated belly, poor appetite, loose stools and aching joints in damp weather. Some texts also used it for night blindness.
It had a second life as a smoke. The dried root was burned in homes, temples and sickrooms to "clear bad air" during outbreaks. The same habit was recorded in Japan, where the root entered Kampo practice as so-jutsu.
These are records of what people did and believed. They are not findings, and this page does not suggest you copy them at home.
Stop and see a doctor if any of these happen: - swelling of the lips, tongue or throat, or trouble breathing (get emergency help) - a spreading rash or hives - yellow skin or eyes, dark urine, or pain under the right ribs - severe stomach pain, vomiting that will not stop, or blood in your stool - shaking, sweating or confusion that may mean low blood sugar
Also see a doctor if bloating, diarrhoea or appetite loss lasts more than two weeks, or if you are losing weight without trying.
In the United States it is sold as a dietary supplement. It is not approved there to treat any illness.
In the UK and the EU it is sold as a herbal or food supplement, not as a licensed medicine. In China and Japan it is a listed medicinal herb used by trained practitioners.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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