What is Qing Gu San?

Qing Gu San is a herbal mix from Chinese medicine. The name means Cool the Bones Powder. It is listed here as a single drug entry, because the herbs are always used together as one formula.

It was given for a low fever that dragged on for weeks. Old texts call this "steaming bone" fever, a heat that seems to rise from deep inside. It was often used when there were also night sweats, a dry mouth, a red tongue, and weight loss.

Here is the plain verdict. We could not find any good human trial of this formula. Its standing rests on long use by Chinese doctors, and long use is not proof that something works.

How does Qing Gu San work?

No one has shown how Qing Gu San works in the body. There is no proven mechanism, and this section is about ideas, not facts.

In Chinese medicine terms, the formula is said to clear "deficiency heat" - a slow, dry sort of heat left after a long illness. Some herbs in it are said to cool, and others to moisten and restore.

Single herbs from the mix have been tested in lab dishes and in animals. Some lower fever or calm swelling in those tests. That does not tell you what the whole formula does in a person.

What forms does Qing Gu San come in?

The classic form is a fine powder. The herbs are ground and taken with warm water.

Today you are more likely to meet it as a decoction (herbs simmered in water to make a strong tea), as granules you stir into hot water, or as small "teapills".

Strength varies a lot between makers. Herb products are not checked as closely as medicines, and some imported herbal powders have been found to contain lead, mercury or hidden drugs. Buy only from a supplier who tests each batch.

Where it comes from:

Qing Gu San comes from a Chinese medical book of 1602, Zheng Zhi Zhun Sheng, written by Wang Ken-tang in the Ming dynasty.

It was aimed at the long, wasting fevers of that era, many of which were most likely tuberculosis (a serious lung infection). It has stayed in Chinese herbal teaching ever since and is still taught in schools today.

That makes it a long-standing staple of one tradition. It has no history outside Chinese medicine.

What does Qing Gu San help with?

• Long-lasting low fever (traditional use): This is the main classic use, and it is the reason the formula exists. We found no human trial testing it for fever. A fever that lasts more than a few days needs a doctor to find the cause first.
• Night sweats: Sweating at night that soaks the sheets is part of the classic picture this formula was built for. There is no trial evidence in people. Night sweats can come from infection, thyroid problems, some cancers and some medicines, so get them checked.
• Feeling hot in the afternoon and evening: Chinese texts describe a heat that rises later in the day and eases by morning. The formula was used for that pattern. No study has measured whether it helps.
• Dry mouth and thirst with a feeling of inner heat: Several herbs in the mix are said to moisten dryness. This is a traditional claim only. A dry mouth can also be a sign of diabetes or a side effect of medicines you already take.
• Weakness left over after a long illness (traditional use): Practitioners use it during slow recovery, when a mild heat and sweating hang on. The support for this is written tradition, not trial data. Tell your doctor what you are taking while you recover.

Which foods are rich in Qing Gu San?

Qing Gu San is not found in food. While taking it, avoid liquorice sweets, liquorice tea and salty liquorice, because they add more glycyrrhizin and raise the same blood pressure and potassium risks.

What are the side effects of Qing Gu San?

• Loose stools or diarrhoea (the bitter cooling herbs can do this)
• Stomach ache or nausea
• Poor appetite
• Puffy ankles or face, from the liquorice
• Raised blood pressure, from the liquorice
• Low potassium, which can cause muscle weakness, cramps and an odd heartbeat
• Headache
• Allergic rash or itching

Good to know:

Most people who take it for a short time have no trouble, or only mild stomach upset. The serious risks come from the liquorice and from long use.

Liquorice can push up blood pressure and pull down potassium, a salt your heart needs to beat evenly. That is a well-known effect in people, and it builds up over weeks.

Because no trial has tracked this formula, we cannot tell you how often side effects happen. Stop it and get advice if anything new starts.

How much Qing Gu San should you take?

• Recommended daily: There is no dose proven safe and useful by research. What follows is common practice, not a standard. A practitioner usually writes the formula for you and adjusts the herbs. Typical daily amounts are about 3 to 9 grams of each dried herb in a decoction, or roughly 6 to 12 grams a day of concentrated granules, split into two doses. Do not build your own version from bulk herbs. The liquorice in it is the part most likely to cause harm at high or long-term doses.
• Best time of day: Usually twice a day, morning and evening. Some practitioners give the evening dose earlier if night sweats are the main problem.
• With or without food: Usually taken warm, between meals, on a fairly empty stomach. If it upsets your stomach, take it just after food instead.
• Time to effect: Traditional teaching expects some change within a few days to two weeks. No study has measured this, so treat it as expectation, not fact.
• How long to take it: Short courses only. Chinese practice uses it for days to a few weeks, until the fever and sweats settle. Stop and rethink after two weeks if nothing has changed. Because of the liquorice, courses longer than four to six weeks raise the risk of high blood pressure and low potassium. Any fever lasting more than a week needs a medical diagnosis, whatever else you are taking.