What is Dan Dou Chi?

Dan Dou Chi is a Chinese herb made from black soybeans that are soaked, steamed and left to ferment. It is also called Fermented Soybean or Prepared Soybean. It is a single herb, not a blend.

In Chinese medicine it is used at the very start of a cold, when you feel chilly, stuffy and warm at the same time. It is also used for a restless, edgy feeling in the chest after a fever. It is almost always boiled into a tea with other herbs.

Traditional use is not proof that a herb works, and we say that once here for the whole page. We could find no human trials of Dan Dou Chi on its own, so its evidence grade is "insufficient". Its place in Chinese medicine, on the other hand, is old and well recorded.

How does Dan Dou Chi work?

No one has shown how Dan Dou Chi works in the body. There is no good lab or human research on this herb by itself, so any explanation below is a guess.

Chinese medicine says it gently "releases the outside", meaning it helps a mild sweat and eases the early stage of a cold. It is also said to settle a hot, restless feeling in the chest.

Fermenting soybeans changes them. It breaks large proteins into smaller pieces and frees up plant compounds. Whether that matters in the small amounts used in a tea is unknown.

What forms does Dan Dou Chi come in?

Whole dried fermented beans, sold loose by weight. This is the usual form and it is boiled into a tea.

Granules or powder made from a water extract, stirred into hot water.

As part of ready-made Chinese formulas, most often with Zhi Zi (gardenia fruit) or with Cong Bai (spring onion white).

Douchi sold as a cooking seasoning in food shops is a related food, not a measured herbal product.

Where it comes from:

Dan Dou Chi appears in the Shang Han Lun, a Chinese medical text from about 200 CE. It is a named part of Zhi Zi Chi Tang, a classic two-herb tea for restlessness after a fever.

It has stayed in everyday Chinese practice for around eighteen centuries. It is a staple of one tradition rather than a herb shared across many, so its traditional tier is T2.

What does Dan Dou Chi help with?

• Early common cold with chills and a stuffy head: This is the main traditional use, usually in the first day or two of feeling unwell. It is paired with spring onion white in a simple tea called Cong Chi Tang. There are no human trials testing Dan Dou Chi for colds. So this rests on tradition alone, not on measured results.
• Mild fever with headache at the start of an illness: Classical texts use it to nudge a light sweat, which was thought to ease a mild fever and head pain. It is seen as gentle, so it was often given to people who were frail. No trial has tested this. If a fever is high, lasts more than three days, or comes with a stiff neck or rash, see a doctor rather than treating it at home.
• Restlessness and poor sleep after a fever has broken: This is the use in Zhi Zi Chi Tang, where it is combined with gardenia fruit. The old description is a hot, fidgety feeling in the chest that stops you settling. Evidence here is traditional only. No published human study has measured sleep or restlessness with this herb.
• Tight, uneasy feeling in the chest during recovery: Practitioners use it for a vague, stuffy chest feeling left over after an illness, with no cough or pain. It is chosen for being mild. Chest tightness has many causes, some of them serious. Get chest pain, pressure or breathlessness checked by a doctor before assuming it is a leftover from a cold.

Which foods are rich in Dan Dou Chi?

1. Douchi, the Chinese fermented black bean seasoning: the same food the herb is made from
2. Natto: Japanese fermented soybeans, high in vitamin K2
3. Miso: fermented soybean paste
4. Tempeh: a pressed fermented soybean cake
5. Soy sauce: brewed from fermented soybeans

Practical Tips:

All of these are fermented soy foods, so the same MAOI antidepressant warning applies to them.

What are the side effects of Dan Dou Chi?

• Wind, bloating or a rumbling stomach
• Loose stools
• Light sweating, which is the intended effect and should be mild
• Nausea if taken on an empty stomach
• Rash, itching, swelling or wheezing in people allergic to soy
• Headache, flushing or a pounding heartbeat in people on MAOI antidepressants

Good to know:

For most people this is a food-like herb and side effects are mild and uncommon. Wind and loose stools are the usual complaints and they settle when you stop.

The two real risks are soy allergy and the MAOI antidepressant clash. Both are rare, but both can be serious, so read the avoid list below.

How much Dan Dou Chi should you take?

• Recommended daily: There is no dose proven by research. The amounts below come from Chinese herbal practice, not from trials. Dried fermented beans: about 6 to 12 g a day, boiled into a tea and split across two doses. Some texts go up to 15 g for a short spell. Granules or extract powder: follow the maker's label, as strength varies a lot between brands. A trained practitioner should set the dose if you are unwell, pregnant, or taking regular medicine.
• Best time of day: Split the tea into two warm doses, morning and early evening. Some practitioners give it warm at the first sign of chills and then again a few hours later.
• With or without food: Usually taken warm, between meals, so it is absorbed quickly. If it upsets your stomach, take it just after food instead.
• Time to effect: Traditionally it is expected to help within hours to a day, since it is used for early, short-lived illness. There is no measured proof of this timing.
• How long to take it: Short courses only. It is a herb for the first few days of a cold, not a daily supplement. Three to five days is typical. If you are no better after three days, or you feel worse at any point, stop and speak to a doctor.