What is Shao Yao Tang?
Shao Yao Tang, also called Peony Decoction, is a set formula of about nine Chinese herbs. It is simmered into a tea and drunk warm. Practitioners give it for diarrhoea that comes with cramping pain, blood or mucus in the stool, and a constant urge to go.
The mix is built around white peony root (Bai Shao) with coptis root (Huang Lian) and Chinese skullcap (Huang Qin). Rhubarb root, areca seed, costus root, angelica root, cinnamon bark and licorice make up the rest. In Chinese medicine the pattern it targets is called damp-heat in the intestines, which is a traditional idea rather than a lab finding.
It has been in use since the 1100s. Long use shows a formula is trusted by its tradition; it does not prove the formula works. Good human trials are few and weak, so treat this page as a guide to a tradition, not proof of benefit.
How does Shao Yao Tang work?
Nobody has shown, in people, exactly how this formula acts. What follows is the traditional reasoning plus lab findings on single herbs.
In Chinese medicine, coptis and skullcap are said to clear heat and damp. Rhubarb root is said to push out what is stuck. Peony root and licorice are said to ease cramping, and cinnamon bark and angelica are said to warm and move the blood so the cold, bitter herbs do not chill the gut.
In the lab, berberine from coptis slows the growth of some gut bacteria and cuts fluid loss from the bowel wall. Rhubarb contains anthraquinones, which are natural laxative chemicals. Peony and licorice can relax smooth muscle, the muscle that squeezes the gut.
These are test-tube and animal results. They suggest why the old use may have taken hold. They do not tell you what the whole tea does inside a person.
What forms does Shao Yao Tang come in?
Raw herb decoction is the classic form. A practitioner weighs out the dried herbs and you simmer them in water, then drink the strained liquid warm.
Granules are the common modern form. The tea is made in a factory, dried, and sold as a powder you stir into hot water.
Pills and tablets exist but are less used for this formula, because doses are usually adjusted per person.
You should not see this as a tincture or an essential oil.
Where it comes from:
The formula appears in Liu Wansu's writings from the Jin dynasty, around 1186. Liu was known for treating illness with cooling, bitter herbs. Shao Yao Tang became the standard answer for hot, painful, bloody diarrhoea and is still taught in Chinese medical schools today.
Who should avoid Shao Yao Tang?
- Do not use if you are pregnant or think you might be: this is a multi-herb formula, and rhubarb root and areca seed in it can make the bowel and the womb contract.
- Do not use if you are breastfeeding: the laxative parts of rhubarb root pass into breast milk and can loosen a baby's stool.
- Do not use if you plan to give it to a newborn or a young baby — berberine, from the coptis in this formula, can push bilirubin (a yellow waste pigment) off its carrier in the blood and cause brain damage in infants.
- Do not use if you have high blood pressure that is not under control, heart failure, or hypokalaemia (low potassium in the blood) — the licorice in it makes all three worse.
- Do not use if you take digoxin (a heart medicine), water pills (diuretics) or steroid tablets, unless your doctor has checked it first.
- Do not use if you take warfarin or another blood thinner, unless your doctor agrees.
- Do not use if you take cyclosporine, tacrolimus or another transplant medicine — berberine can raise their level in your blood.
- Do not use if you have a blocked bowel, or a bowel condition your doctor says could block or tear — the rhubarb root acts as a laxative and is unsafe then.
- Do not use if your diarrhoea is long-standing, watery and painless with no fever — this formula is aimed at hot, painful, bloody stools, and the cold bitter herbs can upset a weak gut.
- Do not use if you have kidney disease or liver disease, unless a doctor who knows your case says it is fine.
- Do not use if you are already taking senna, lactulose or another laxative — the effects add up.
When should you see a doctor?
See a doctor now, rather than treating this at home, if you notice any of these:
Blood in your stool, or black tarry stools. A fever above 38.5C. Diarrhoea that lasts more than two days in an adult, or more than one day in a child or an older person.
Severe or steady belly pain. Signs of drying out, such as very little urine, dizziness on standing, or a dry mouth.
Also get advice if you are already taking this formula and your ankles swell, you get headaches, your heartbeat feels odd, or you feel very weak. Stop it and call your doctor or pharmacist.
And see a doctor if you simply are not better after three days on it.
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