What is Qin Pi?

Qin Pi is the dried bark of several ash trees, most often Fraxinus rhynchophylla or Fraxinus chinensis. It is also known as Korean ash bark or Chinese ash bark. This document covers it as a single drug (TCM herb), not as part of a named formula.

In traditional Chinese medicine it is used as a bitter, cooling herb for watery or bloody diarrhoea, for hot swollen eyes, and for vaginal discharge. It is nearly always cooked into a water decoction (a strong tea simmered from the bark) and combined with other herbs.

Here is the honest verdict up front: Qin Pi has a long and steady record in one tradition, but almost no human trial evidence of its own. Traditional use tells you what people have done for centuries; it is not proof that the herb works. Read the safety section below before trying it.

How does Qin Pi work?

Nobody has shown clearly how Qin Pi works in people. What follows is a proposed explanation, not a proven one.

Its main compounds are coumarins, a family of plant chemicals. In laboratory dishes and in animals, these compounds slow the growth of some bacteria, calm inflammation (swelling and irritation in tissue), and mop up unstable molecules called free radicals.

One of them, esculin, is chemically related to compounds used in some vein products, which is why bleeding risk is treated as a real theoretical concern. None of this has been confirmed by human trials of the bark itself.

What forms does Qin Pi come in?

Qin Pi is sold and used in a few forms:

Dried shredded or rolled bark, simmered into a decoction (a strong tea boiled from the bark). This is the classical form.

Granules or concentrated powder made from a decoction and dried, usually stirred into hot water.

As an ingredient inside multi-herb patent formulas in tablet or pill form.

Occasionally as a wash or eye rinse in traditional practice. Do not put home-made herb liquid in your eyes; the risk of infection and injury is real.

Where it comes from:

Qin Pi appears in the Shen Nong Ben Cao Jing, the foundational Chinese herbal text compiled around the first to second century CE, and has stayed in continuous use since.

Classical texts place it in the group of herbs that clear heat and dry dampness. Its best known appearance is in Bai Tou Weng Tang, a formula for dysentery-type diarrhoea.

It is also recorded in Korean and Japanese Kampo practice, but its main home is Chinese medicine.

What does Qin Pi help with?

• Watery or bloody diarrhoea: This is the classic traditional use and the one with the longest record. The bark is astringent, meaning it tightens tissue, which fits the traditional reasoning. No published human trial has tested Qin Pi on its own for diarrhoea. Diarrhoea with blood, fever or dehydration needs medical care, not herbs.
• Dysentery-type gut infections: Traditional practice uses Qin Pi inside the formula Bai Tou Weng Tang rather than alone. Laboratory work shows its coumarins slow the growth of some bacteria in a dish. That is a long way from showing it treats an infection in a person, and it should never replace antibiotics when those are needed.
• Red, hot, sore eyes: Traditional texts describe a decoction used as an eye wash for redness and swelling. There is no modern human evidence for this, and non-sterile liquids in the eye can cause serious infection. Eye pain, vision change or discharge needs a doctor the same day.
• Vaginal discharge with itching: Classical use is as a wash or as part of an internal formula for what is described as damp-heat discharge. No human trials support it. New, smelly or bloody discharge, or discharge with pelvic pain or fever, should be checked by a clinician.
• Gout and joint pain: Interest here comes from test-tube work suggesting esculetin can slow an enzyme involved in making uric acid, the substance that forms gout crystals. This has not been tested in people using Qin Pi. Do not swap gout medication for this herb.

Which foods are rich in Qin Pi?

Qin Pi is tree bark used as a medicine, not a food, and it is not found in any diet.

What are the side effects of Qin Pi?

• Nausea
• Stomach ache or cramping
• Loss of appetite
• Worsening loose stools in some people
• Skin rash or itching (allergic reaction)
• Passing more urine than usual
• Easier bruising or longer bleeding from small cuts (uncommon, and a reason to stop)

Good to know:

Most reported problems are mild stomach upset and settle when the herb is stopped. Because Qin Pi is a bitter, cooling herb, people who already run cold, tire easily or have chronic loose stools tend to feel worse on it.

The coumarins it contains are the reason bleeding is watched for. Serious harm from normal traditional doses is not well documented, but this partly reflects how little formal study exists rather than proven safety.

Stop taking it and seek advice if you notice unusual bruising, blood in your stool, a rash, or yellowing of your skin or eyes.

How much Qin Pi should you take?

• Recommended daily: No dose has been established by research. What follows is the range used in traditional practice, not a recommendation. Traditional Chinese texts and modern pharmacopoeia listings use roughly 6 to 12 grams of dried bark per day, simmered into a decoction and usually split across two servings. Granule and tablet products vary in strength, so follow the label on the product you hold. Higher doses are not better and raise the chance of stomach upset. A qualified practitioner should set the amount, especially since Qin Pi is normally used inside a formula rather than alone.
• Best time of day: Traditionally taken in two doses, morning and evening. Some practitioners give it between meals for gut complaints. There is no research showing that timing changes the result.
• With or without food: Usually taken warm, between meals, in traditional practice. If it upsets your stomach, take it with food instead.
• Time to effect: Traditional practice expects to see change in an acute gut or eye complaint within a few days. There is no trial data to confirm any time frame.
• How long to take it: Traditional use is short and targeted, usually a few days to about two weeks for an acute problem. If diarrhoea, eye redness or discharge has not clearly improved within 2 to 3 days, stop and get medical advice. Long-term daily use has not been studied for safety and is not advised.