What is Quan Shen?

Quan Shen is the dried underground stem (rhizome) of bistort, Polygonum bistorta. In Chinese medicine it is used as a drying, binding herb for loose stools, for sore mouth and throat, and for small bleeds. It is also used on the skin as a wash for sores.

The honest verdict on proof is short. We could find no human trials of Quan Shen on its own, so its use rests on tradition and on lab work. Long traditional use is not proof that a herb works, and that is true of this one.

Its safety tier is routine. That means short-term use of normal amounts is low risk for most healthy adults. Some people still need to avoid it, and it can clash with a few common medicines, so read the safety notes below.

How does Quan Shen work?

The best-supported idea is simple: Quan Shen is astringent, meaning it dries and tightens tissue.

It is high in tannins. Tannins bind to proteins on the surface of the gut and the mouth. In theory this forms a thin protective layer, which may slow the loss of fluid in diarrhoea and calm a raw surface.

Lab studies also report that its extracts can slow the growth of some bacteria and can mop up free radicals (unstable molecules that damage cells). These are test-tube and animal findings. They do not show that the herb helps a person who is ill.

What forms does Quan Shen come in?

The usual form is dried sliced rhizome, simmered in water to make a decoction (a strong tea made by boiling). This is how it is most often given in Chinese practice.

You may also see it as a plain powder, or as granules that dissolve in hot water. Some Western herb suppliers sell an alcohol tincture (a liquid extract).

For the mouth and throat, the cooled decoction is used as a gargle. For skin sores, the same liquid is used as a wash or a soaked cloth. Quan Shen is rarely sold as a standard capsule.

Where it comes from:

Quan Shen is recorded in Chinese materia medica texts by the Song era, roughly the 10th to 13th century. It sits in the group of herbs described as clearing heat and resolving toxins, and as stopping bleeding.

In Chinese formulas it is usually a supporting herb rather than the lead one. The same plant has a long separate history in Europe, where bistort root was a folk remedy for diarrhoea and mouth sores.

What does Quan Shen help with?

• Short-term diarrhoea: This is the main traditional use, and the one that fits the herb's chemistry best. Tannins tighten the lining of the gut, which may slow fluid loss. No human trial of Quan Shen for diarrhoea turned up in our search. Fluids and salts remain the first thing that matters in any bout of diarrhoea.
• Dysentery-type diarrhoea (loose stools with blood or mucus): Classical texts use Quan Shen here, often with other herbs. Lab tests show its extracts can slow some gut bacteria. This is not a home problem. Blood or mucus in your stools, with fever, needs a doctor and often needs a test to find the cause.
• Sore mouth, gums and throat: Traditionally the cooled decoction is swished or gargled, then spat out. The dry, binding taste may make a raw surface feel less sore for a short while. We found no human trials for this use. It does not treat the cause of an infection.
• Minor bleeding, such as a nosebleed: Chinese texts list Quan Shen among herbs said to stop bleeding, and European folk use matches that. Astringent tannins can tighten small surface vessels. Human proof is absent. Bleeding that will not stop, or bleeding you cannot explain, needs urgent care rather than a herb.
• Skin sores, boils and minor burns: The wash is a traditional outside use for weeping or angry-looking skin. Some animal work suggests tannin-rich extracts may help wounds close, though results vary. Keep it off deep wounds and large burns. Those need proper cleaning and dressing by a clinician.

Which foods are rich in Quan Shen?

1. Bistort leaves: the young spring leaves of the same plant are eaten as a green in parts of northern England
2. Black tea: a common food source of the same tannins
3. Pomegranate: also tannin-rich, with the same dry taste

What are the side effects of Quan Shen?

• Mild stomach upset or a feeling of sickness
• Constipation, since the herb dries and binds
• A dry, puckering feeling in the mouth
• Less iron taken up from food, with long use
• Skin rash, rarely, in people allergic to the plant

Good to know:

Most people who use it for a few days have no trouble at all. The usual complaint is a mild upset stomach. It tends to pass once you stop.

Long use is the bigger worry. Tannins can cut how much iron your body takes in from food. If you use it for weeks, watch for tiredness or pale skin, and see a doctor.

Stop the herb if you get a rash, swelling or belly pain. Get help the same day if a rash spreads fast or your lips or tongue swell.

How much Quan Shen should you take?

• Recommended daily: There is no modern dose set by trials, because the trials have not been done. Chinese practice commonly uses about 5 to 10 grams of dried rhizome a day, simmered in water and split into two drinks. Some texts allow a little more for a short spell. For a gargle or skin wash, a stronger brew is made and used cool. Do not swallow the wash. If a practitioner has given you a formula, follow their amount, not a general figure.
• Best time of day: Spread the day's amount over two drinks, one in the morning and one in the evening. There is no evidence that a set clock time works better.
• With or without food: Take it between meals, on a fairly empty stomach, which is the usual practice for decoctions. If it makes you feel sick, take it with a little food instead. Keep it at least two hours apart from iron pills and other tablets.
• Time to effect: If it helps at all, the effect on loose stools is usually felt within a day. A gargle may soothe a sore throat within minutes, but that relief is brief.
• How long to take it: Use it for days, not weeks. Three to five days is the normal traditional span for a bout of diarrhoea. Stop and reassess if nothing has changed after two days. Long runs of a tannin-rich herb can lower how much iron your body takes in, so avoid weeks of daily use unless a practitioner is guiding you.