Wen Pi Tang
Do not self-treat with Wen Pi Tang
Practitioner-prepared only. This formula holds aconite and licorice, so the amount must be set by a trained herbal practitioner or a doctor who knows it.
If this is an emergency
Some reactions to Wen Pi Tang need urgent care. Call your local emergency number or go to an emergency department straight away — do not wait to see whether it passes.
Who should avoid Wen Pi Tang?
- Never use this formula on your own: take it only under a trained herbal practitioner or a doctor who knows it contains aconite.
- Never use raw or unprocessed aconite (Fu Zi), or a product that cannot confirm the aconite was properly processed; raw aconite has killed people.
- Do not use if you are pregnant or trying to get pregnant, because rhubarb and aconite can harm a pregnancy.
- Do not use if you are breastfeeding.
- Do not give it to children.
- Do not use if you have any heart rhythm problem (an uneven, skipping or racing heartbeat), heart failure or heart disease.
- Do not use if you take digoxin, water pills (diuretics), steroid tablets or medicine for heart rhythm.
- Do not use if you have high blood pressure.
- Do not use if you have low potassium (hypokalaemia, meaning low levels of a mineral your heart and muscles need).
- Do not use if you have a blocked bowel, belly pain with no known cause, or inflammatory bowel disease (long-term swelling and sores in the gut).
- Do not use if you have liver disease, or kidney disease that a doctor is not actively managing with you.
- Do not use if you are due to have surgery within the next two weeks.
- Do not take it daily for weeks on end without a doctor checking your blood pressure and potassium.
When should you see a doctor?
Stop taking it and get emergency help straight away if your lips, tongue, face or fingers go numb or tingle, your heart pounds or skips, you feel faint, or you vomit and feel very weak. These can be signs of aconite poisoning, which can be fatal.
Call a doctor soon if you get swollen ankles, bad headaches, muscle weakness or cramps. These can mean the licorice has pushed up your blood pressure or dropped your potassium.
See a doctor if constipation lasts more than a week, or if diarrhoea leaves you dizzy or unable to keep fluids down.
Get urgent care for belly pain with fever, blood in the stool, vomiting, or no wind passing, whether or not you are taking this formula.
- What it is: A classical Chinese herbal formula of rhubarb, prepared aconite, dried ginger, ginseng and licorice, used for constipation in someone who feels cold and weak.
- Active ingredients: Anthraquinones from rhubarb root, such as sennoside and emodin, Aconitine-type alkaloids from prepared aconite root, Gingerols and shogaols from dried ginger, Ginsenosides from ginseng, Glycyrrhizin from licorice root
- Side effects: Diarrhoea and cramps are common; licorice can raise blood pressure and drop potassium, and aconite can harm the heart.
- Pregnancy & breastfeeding: Avoid in pregnancy and while breastfeeding.
Educational information, not medical advice — ask your doctor or midwife.
What is Wen Pi Tang?
Wen Pi Tang is a Chinese herb formula. Its name is usually put into English as Warm the Spleen Decoction. A decoction is a strong tea made by boiling herbs.
It is a set mix of herbs. Most blends use rhubarb root, prepared aconite root, dried ginger, ginseng and licorice root.
We list it here as one item, a TCM formula, even though it holds several herbs. Herbalists in China and Japan use it for constipation. It is used when a person feels cold, tired and crampy.
In Japan, a granule form has also been given with standard care for long-term kidney disease.
Here is the short verdict on the evidence. Human trial evidence is thin. Long use in tradition is not proof that a remedy works.
This formula also holds aconite and licorice. Both can cause serious harm. It is not a self-care remedy.
Use it only under a trained practitioner or a doctor.
How does Wen Pi Tang work?
No one has shown clearly how Wen Pi Tang works in people. What follows mixes old theory with lab findings. It is not settled fact.
In Chinese medicine terms, the formula is said to warm a cold, weak gut. At the same time, it is said to move stuck stool down.
Rhubarb root is the part that moves the bowel. Dried ginger and prepared aconite are added to offset what practitioners call the cold nature of rhubarb.
In the lab, rhubarb compounds lower some waste products in rats with damaged kidneys. They also lower markers of kidney stress.
Ginseng and licorice compounds show mild swelling-calming effects in cell studies.
Does any of this happen in a human body, at a dose that is safe to take? That has not been shown.
What forms does Wen Pi Tang come in?
The old form is a decoction. The dried herbs are boiled in water. You drink the liquid, usually split over the day.
A dried granule extract is common in Japan. There the formula is called Onpito. You stir it into hot water.
Pills and tablets also exist.
Form matters here more than usual. Aconite is only fairly safe when it has been processed the right way. You cannot judge that by looking at a product.
Buy only from a regulated pharmacy or a licensed practitioner. They can confirm the source.
Where it comes from:
Wen Pi Tang comes from a Tang dynasty book in China, written around 652 CE. The author was Sun Simiao. The book is Bei Ji Qian Jin Yao Fang (Essential Formulas Worth a Thousand Gold Pieces).
It has stayed in use in Chinese herb practice ever since. It also entered Japanese Kampo medicine as Onpito. From the late 1900s, Japanese researchers studied it in animals with kidney damage.
It is a long-standing staple of one tradition. It is not a remedy shared across many separate systems.
What does Wen Pi Tang help with?
- Constipation with cold and cramping: This is the formula's classic use. Old texts describe hard, stuck stools in a person who feels cold, weak and crampy. Rhubarb root is a known laxative, so a bowel effect is expected. That part is not in doubt. What is missing is testing. We found no good human trial of the whole formula for constipation.
- Cramping belly pain with cold hands and feet: Tradition links this kind of pain to a weak, cold gut. Dried ginger and prepared aconite are the warming herbs in the mix. Support for this use is text-based and comes from practice, not from trials. Belly pain has many causes, and some are serious. Get pain checked by a doctor first, above all if it is new, bad or comes with fever.
- Long-term kidney disease, as an add-on in Japan: This is the use most often studied. In Japan the granule form has been given with normal medical care in slow kidney decline. Most of that work was done in rats, not people. The few human reports are small and were not well controlled. So we cannot say the formula helps kidneys. Never use it in place of the care your kidney doctor gives you.
- Poor appetite and tiredness in someone who feels cold: Ginseng and dried ginger are the herbs aimed at this. Practitioners pick the formula when low energy comes with a cold feeling and slow bowels. There is no trial evidence for this use. Ongoing tiredness needs a check-up, since low iron, thyroid trouble and other causes are common and treatable.
What are the side effects of Wen Pi Tang?
- Loose stools, urgency or watery diarrhoea
- Belly cramps and gurgling
- Nausea
- Yellow or orange coloured urine from the rhubarb, which is harmless
- Swollen ankles and a rise in blood pressure, from the licorice
- Muscle weakness or cramps from low potassium (a mineral your heart and muscles need)
- Numbness or tingling of the lips, tongue or fingers, which is a warning sign of aconite poisoning
- A pounding, skipping or racing heartbeat
- Feeling faint, sweaty or very weak
Good to know:
Loose stools and cramping are common and expected, because rhubarb is a laxative. They usually settle when the dose is lowered.
The licorice effects build slowly over weeks of steady use. Swollen ankles, headaches or muscle weakness are the usual first signs.
The aconite effects are the dangerous ones. Tingling lips, an odd heartbeat or faintness are not mild side effects. Stop the formula and get emergency help at once.
Options to discuss with a clinician
For each of the problems this formula is reached for, there are better-studied routes — and each one is a conversation to have with a doctor, pharmacist or qualified herbalist rather than a straight swap you make at home.
- **Constipation with cramping:** Psyllium Husk, Supplemental fiber, Partially hydrolyzed guar gum, Inulin, Resistant Starch (RS2/RS3) and Magnesium are all options a clinician can help you weigh up. Stimulant laxatives such as Senna (Unani), Rhubarb Root (Persian Rewash) or Cascara sagrada are short-term tools that need a pharmacist's input, as they are not for ongoing use. - **Cramping belly pain:** Peppermint Oil and Probiotics have the strongest evidence base here; Massage Therapy and Acupressure are low-risk things to ask about. Persistent cramping deserves a proper diagnosis first — a doctor will want to rule out causes that need treating directly. - **Long-term kidney disease:** This belongs with a kidney specialist (nephrologist). Many herbs and supplements are cleared by the kidneys and can build up, so bring anything you are considering to that appointment before starting it. - **Feeling cold, tired, poor appetite:** Ask for blood tests — thyroid problems, anaemia (low iron) and low Vitamin D all look like this and are treatable once identified.
Graded pages for the options named above:
- Partially hydrolyzed guar gum — evidence grade B, traditional tier T0
- Rhubarb Root (Persian Rewash) — evidence grade B, traditional tier T3
- Resistant Starch (RS2/RS3) — evidence grade B, traditional tier T0
- Supplemental fiber — evidence grade A, traditional tier T0
- Cascara sagrada — evidence grade C, traditional tier T2
- Massage Therapy — evidence grade B, traditional tier T3
- Peppermint Oil — evidence grade A, traditional tier T2
- Psyllium Husk — evidence grade A, traditional tier T3
- Senna (Unani) — evidence grade A, traditional tier T3
- Acupressure — evidence grade B, traditional tier T3
- Probiotics — evidence grade A, traditional tier T0
- Magnesium — evidence grade A, traditional tier T0
- Vitamin D — evidence grade A, traditional tier T0
- Inulin — evidence grade A, traditional tier T0
Review status
This page has not been signed off by a pharmacist and is not published. It is shown here for a policy decision only.