What is Xie Huang San?

Xie Huang San is a herb blend used in Chinese medicine. The name is often put into English as "Drain the Yellow Powder". It is made from five herbs, most often mixed as a powder or boiled as a tea.

It has long been given for sore mouths. Old texts use it for mouth ulcers (small sores inside the mouth or on the tongue), bad breath, dry lips and thirst. It was used a lot for children.

Here is the short verdict on proof. The formula is well known and has been used for centuries, but we could not find any human trial of it. A long record of use is not the same as proof that something works.

One herb in the blend is licorice root. That matters for safety, so please read the next part before you try it.

How does Xie Huang San work?

No one has shown how this blend acts in the body. What follows is the traditional idea, plus what lab work hints at.

In Chinese medicine the formula is said to clear "heat in the Spleen and Stomach". In plain words, that is a pattern of a red, sore, dry mouth with thirst and bad breath. The herbs are picked to cool that heat without drying the person out.

Lab and animal work on single herbs points a few ways. Gardenia fruit and licorice root both calm swelling and redness in test animals. Licorice root also coats and soothes sore lining in the mouth and gut.

Those findings come from dishes and animals, not from people taking this blend. So treat the mechanism as an idea, not a fact.

What forms does Xie Huang San come in?

You may see it as a loose powder made from the five ground herbs. This is the oldest form.

It also comes as dried granules that you stir into hot water, and as pills or capsules from Chinese herb suppliers.

Some herbalists boil the raw herbs into a tea. The blend is not usually sold as a tincture (an alcohol extract).

Amounts of each herb vary a lot between makers. Herb products are not checked as closely as drugs, so quality differs by brand.

Where it comes from:

The formula comes from a Song dynasty book on children's health, written by Qian Yi around 1119 CE. That book is one of the first works on treating children in Chinese medicine.

It still appears in standard Chinese formula textbooks today. It is best known as a children's formula for mouth sores, though adults have used it too.

What does Xie Huang San help with?

• Mouth ulcers (small sores inside the mouth): This is the main old use, and it is why the formula was written down. Healers gave it for sores on the tongue, lips or cheeks that look red and feel hot. We found no trial that tested the blend for mouth sores in people.
• Bad breath: Old texts link bad breath to "Stomach heat" and list this blend for it. There is no trial support. Bad breath most often comes from gum disease, tooth decay or a coated tongue, so see a dentist first.
• Dry mouth and thirst: Traditional use covers a dry mouth with a strong wish to drink cold water. No trial has tested that use. A lasting dry mouth can also come from medicines, diabetes or a gland problem, and those need a doctor.
• A red, sore tongue: In Chinese medicine a red tongue with a yellow coat is one of the signs a practitioner looks for before giving this blend. It is a way of matching the herb to the person, not a tested outcome.
• Restless children with a sore mouth: The source text is a children's book, and it describes fussy, hot, thirsty children with mouth sores. Modern testing in children is missing. Because the blend holds licorice root, do not give it to a child on your own.

Which foods are rich in Xie Huang San?

1. Licorice sweets and licorice tea: they hold the same licorice root, so they add to your total
2. Gardenia used as a yellow food colour in some Asian rice and pickle dishes — the food amounts are small

Practical Tips:

If you take this blend, cut out licorice sweets and licorice tea while you do.

What are the side effects of Xie Huang San?

• Loose stools or mild belly cramps
• Feeling sick to your stomach
• Puffy ankles, hands or face (the body holding water)
• Raised blood pressure (more force in your blood vessels)
• Low potassium, which can leave you weak or crampy
• Headache, from the same water and salt shift
• Rash or itch, if you react to one of the herbs

Good to know:

Most people who take this for a few days have no trouble. The most common gripe is loose stools, since gardenia fruit can act as a mild laxative (it loosens the bowels).

The bigger worry is licorice root. Taken in large amounts, or for weeks on end, it can make you hold water, push your blood pressure up and drop your potassium. Low potassium can cause weak muscles and an uneven heartbeat, and in rare cases people have needed hospital care.

This risk goes up if you already have heart, kidney or blood pressure problems, or if you also eat real licorice sweets. Keep the course short, and stop if you swell up or feel weak.

How much Xie Huang San should you take?

• Recommended daily: There is no dose set by research. What follows is common practice, not a tested amount. Herbalists often use 6 g to 9 g of the dried blend a day, split into two or three drinks. Ready-made granules are usually 2 g to 3 g, taken two or three times a day. Always follow the label on the product you buy. Children need a smaller amount worked out for their size. Ask a trained herbalist or your doctor first.
• Best time of day: Spread the doses through the day, such as morning and evening. There is no evidence that one time of day works better.
• With or without food: Usually taken between meals with warm water. If it upsets your stomach, take it with a little food.
• Time to effect: Traditional use suggests a few days. If nothing has changed in a week, it is time to stop and ask a doctor or dentist.
• How long to take it: This blend is meant for short use. Most herbalists give it for a few days up to about one week, until the mouth feels better. Do not keep taking it for weeks. The licorice root in it can build up and cause swelling, raised blood pressure and low potassium. Stop and check in with a doctor if your mouth is no better after seven days.