Qing Dai

What is Qing Dai?

Qing Dai is a dark blue powder made from indigo plants. In Chinese medicine it is given for what the tradition calls heat, such as fevers, rashes, mouth sores and bleeding. Today it is best known as a herb tried for ulcerative colitis, a disease that inflames the large bowel.

It is a single herb, not a mixed formula. So you take a strong dose of one plant, with nothing else in the mix to soften it.

The picture is mixed. Human trials in ulcerative colitis do show a real effect on the bowel. But the same herb has harmed the lungs and the liver in some people, and one trial was stopped early for that reason.

Long traditional use is not proof that a herb works, and it is not proof that a herb is safe. This page reports both axes on their own terms: what the tradition says, and what trials show.

How does Qing Dai work?

Nobody can say for sure how Qing Dai works in the gut. The leading idea is hedged and comes mostly from lab and animal work.

Its blue pigments seem to switch on a sensor on immune cells called the aryl hydrocarbon receptor (a control switch that helps calm inflammation in the gut lining). In animals, turning this switch on cools bowel inflammation and helps the lining heal.

The same switch may also drive the harm. Long, strong use is thought to narrow the small blood vessels in the lungs and to stress the liver. That is why dose and time matter so much here.

What forms does Qing Dai come in?

Qing Dai comes in a few common forms: - Loose blue powder, stirred into water and swallowed - Capsules of the plain powder - Skin creams and ointments, used mainly for psoriasis (a scaly skin disease) - Throat and mouth powders, blown or dabbed on sores - As one herb inside a larger Chinese formula

The powder stains. It turns the tongue, the stool and cloth blue-green.

Where it comes from:

Qing Dai has been used in Chinese medicine for well over a thousand years, with records from the Tang era onward. Classic texts place it in the group of cold herbs used to clear heat and cool the blood.

It later became a staple in Japanese Kampo medicine too, under the name seitai. Indigo plants are dyes in many cultures, but this medical use is chiefly a Chinese one.

What does Qing Dai help with?

• Ulcerative colitis (inflammation of the large bowel): This is the one use with real trial support. A placebo-controlled trial found that more people improved on the herb than on a dummy powder over 8 weeks. That trial was stopped early after a safety problem in the lungs, so the benefit and the risk sit side by side. It is not a cure, and it is not a self-care herb.
• Psoriasis (a scaly skin disease): Small trials of indigo naturalis ointment on the skin showed plaques got thinner and less red. The trials were short and small. Rubbing it on the skin avoids most of the gut and lung risk, but it stains skin and clothes.
• Mouth and throat sores: A classical use. The powder is dabbed on sore spots or gargled in water. There are no good human trials for this use, so the support is traditional only.
• Fever with a red rash: Traditional use in children and adults for high fever with rash. Modern trials have not tested this. A fever with a rash in a child needs a doctor, not a herb.
• Nosebleeds and other bleeding the tradition calls heat in the blood: Old texts use Qing Dai to cool the blood and stop nosebleeds or coughing of blood. No human trials back this. Bleeding you cannot explain always needs a medical check.
• Mumps and swollen glands (traditional use): Applied as a paste over swollen glands in classical practice. Evidence here is tradition and case reports, not trials.

What are the side effects of Qing Dai?

• Blue-green stool and a stained tongue (harmless, but expect it)
• Nausea and belly pain
• Headache
• Diarrhoea
• Raised liver blood tests, and in some cases real liver injury
• Ischaemic colitis (a sudden loss of blood flow to part of the bowel), with cramping pain and bloody stool
• Intussusception (one part of the bowel sliding into the next), reported mainly in younger users
• Pulmonary arterial hypertension (high blood pressure in the lung blood vessels), which can be lasting and life-threatening

Good to know:

Most people get only the blue stool and mild gut upset. The serious problems are much rarer, but they are severe and some have needed hospital care or surgery.

High blood pressure in the lung blood vessels is the reason Japanese health bodies warned about this herb. It caused a trial to be halted early. Some people improved after stopping the herb; others did not fully recover.

This is not a herb where a mild side effect list tells the whole story. Treat any new breathlessness as urgent.

Options to discuss with a clinician

If your concern is ulcerative colitis, there are gentler options you could raise with a doctor. People often ask about aloe vera gel taken by mouth, curcumin from turmeric as an add-on, or psyllium husk. Probiotics are another option worth asking about.

For scaly skin patches, plain moisturisers, oatmeal baths and gentle coal tar preparations are milder things to ask about. None of these carry the lung and liver concerns linked to this herb. Bring the list to your doctor or another clinician, who can say what suits your case and what fits with your current treatment.

Graded pages for the options named above:

• Psyllium Husk — evidence grade A, traditional tier T3
• Probiotics — evidence grade A, traditional tier T0
• Aloe Vera — evidence grade B, traditional tier T3
• Curcumin — evidence grade A, traditional tier T0