Educational information, not medical advice — ask your doctor or midwife.
Bai Mao Gen is the dried root and stem of woolly grass (Imperata cylindrica). The stem part grows under the ground. Chinese herbal medicine uses it as a cooling, mild diuretic (a thing that makes you pass more urine).
It is one herb, not a blend. Most people take it as a decoction (a tea made by simmering the root).
Tradition gives it for nosebleeds, blood in the urine, and hot burning urine. It is also used for thirst with fever, and for puffiness from fluid build-up. Modern kitchens in southern China make it into a cooling summer drink.
The honest verdict: the record of traditional use is long and clear. But good human trial evidence is thin, and such use alone is not proof that a thing works. Nothing here is a cure or a promise of an outcome.
No one has shown clearly how Bai Mao Gen works in people. Old theory says it clears heat from the blood. It is also said to stop bleeding and move water down through the bladder.
Lab and animal work points to a mild rise in urine. It also hints at some anti-inflammatory (swelling-calming) action. This may come from the sugars and plant acids in the root.
Those findings come from test tubes and animals. They may not carry over to you. It is best seen as a gentle, watery, food-like herb, not a strong drug.
Bai Mao Gen comes in several forms:
Dried cut root, simmered into a tea. This is the usual form.
Fresh root, juiced or simmered. This form is a favourite in southern China.
Granules or powdered extract that melt in hot water.
Charred root (Bai Mao Gen Tan). Tradition uses this form when bleeding is the main worry.
Ready-made bottled cooling drinks. These are often mixed with sugarcane or water chestnut.
Bai Mao Gen appears in the Shen Nong Ben Cao Jing. That is a Chinese herb text from about the first or second century CE. Chinese medicine has used the root without a break since then.
It is used there for bleeding, heat and problems with urine. It is a long-standing staple of that one tradition. It is not a herb shared across many traditions.
See a doctor straight away if you see blood in your urine, cough up blood, have a nosebleed that will not stop after 15 minutes of pressure, or your skin or eyes turn yellow. Get medical help if you have burning urination with fever or back pain, since that can mean a kidney infection. Also stop the herb and get checked if you feel faint, get muscle cramps, swell up more, or develop a rash, swollen lips or trouble breathing.
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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