What is Da Ji?

Da Ji is a Chinese herb used to help slow bleeding. It is the root and leafy top of Japanese thistle, a spiky plant. It is a single drug, not a blend of herbs.

Old Chinese books put it with herbs that "cool the blood". Healers gave it for nosebleeds, blood in the urine, coughing up blood, and heavy periods. Folk use also covers boils and hot, sore skin lumps.

Here is the short verdict. We could find no good human trials, so we cannot say it works. Long use in a tradition is not proof of effect, and that holds for every claim on this page.

How does Da Ji work?

The honest answer is that no one knows for sure.

Lab and animal work hints that the plant chemicals in Da Ji may help blood clot a bit faster. Some animal work also hints at lower blood pressure. None of this has been shown in people.

Chinese medicine has its own words for it. It is said to cool heat in the blood, stop bleeding, and break up lumps. Those are ideas from an old system, not lab findings.

What forms does Da Ji come in?

Most often you meet Da Ji as dried, cut herb for a tea. The tea is made as a decoction, which means a long simmer. Both the root and the top of the plant are used.

A charred form, called Da Ji Tan, is made by roasting the herb until it is black. Chinese medicine picks this form when the aim is to slow bleeding.

You may also see powders, granules, drops, and ready-made pills. Fresh juice is a folk form in China.

It is often one part of a mixed formula, such as Shi Hui San (Ten Charred Herbs Powder), rather than taken on its own.

Where it comes from:

Da Ji has been named in Chinese herb books since about 500 CE. The first known entry is in the Ming Yi Bie Lu, a record of famous doctors.

It stayed in use through later herb books and is still on China's official herb list today. It is also used in Korea and Japan, where young thistle shoots are eaten as food.

Its job has been much the same in every era: to slow bleeding and cool what old texts called heat in the blood.

What does Da Ji help with?

• Bleeding from the nose: This is a classic use in Chinese medicine, often with the charred form. We found no human trial that tests it. A nosebleed that will not stop after 20 minutes of pinching needs a doctor, not a herb.
• Coughing up blood: Old texts list this as a main use. There is no trial proof. Coughing up blood can point to a serious lung or heart problem, so it must be checked by a doctor first.
• Blood in the urine: Traditional use is strong here and the herb is often paired with Xiao Ji (small thistle). Human proof is missing. Blood in the urine always needs a medical check, since causes include infection, stones and cancer.
• Heavy or long monthly periods: Chinese medicine uses it for heavy bleeding said to come from heat. No human trial supports this. Heavy periods can cause low iron, so ask a doctor rather than self-treating for months.
• Blood in the stool or from piles: Listed in old formula books for this use. Evidence in people is missing. Blood in the stool needs a doctor's check before you treat it yourself.
• Boils and hot skin sores: Fresh crushed herb was applied to the skin in folk practice. This use rests on tradition only. Spreading redness, fever or a hot swollen limb means you need care that day.
• Liver complaints (folk use only): Some Chinese reports describe Cirsium extracts used for hepatitis (liver swelling). We could not find a clear, well-run human trial, so treat this as folk use, not proof.
• High blood pressure (folk use only): Animal work hints at a small drop in blood pressure. Nothing reliable has been shown in people. Do not swap your blood pressure tablets for this herb.

Which foods are rich in Da Ji?

1. Young thistle shoots (azami): eaten as a spring vegetable in Japan
2. Korean thistle greens: blanched and dressed as a side dish
3. Thistle root pickles: a country food in parts of China and Korea

Practical Tips:

Food amounts of thistle greens are far smaller than medicinal doses and are not a way to treat bleeding.

What are the side effects of Da Ji?

• Upset stomach or queasiness
• Loose stools
• Loss of appetite
• Dry mouth
• Skin rash or itch in people allergic to daisy-family plants
• Possible drop in blood pressure, which may cause dizziness

Good to know:

Reports of harm from Japanese thistle itself are few, but that is partly because it has barely been studied in people. Most listed effects are mild and stop when you stop the herb.

The bigger risk is a mix-up in the shop. A different and much harsher herb, Peking spurge (Euphorbia pekinensis), is also sold under a Da Ji name and can cause violent vomiting and diarrhoea. Check the Latin name on the label.

How much Da Ji should you take?

• Recommended daily: No dose has been set by human trials. The doses below come from Chinese practice, not from proof. In Chinese herb books the usual amount is 9 to 15 grams of the dried herb, simmered as a tea. Fresh herb is used in larger amounts, often 30 to 60 grams. The charred form is used in smaller amounts inside a mixed formula. If you use a ready-made product, follow the label and do not take more than it says.
• Best time of day: Usually split into two doses, morning and evening. There is no proof that timing changes the result.
• With or without food: Taken with or just after food is easier on the stomach. The bitter tea can cause queasiness on an empty stomach.
• Time to effect: Unknown. Tradition treats it as a short-term herb for the days of bleeding, but no trial has measured how fast it acts in people.
• How long to take it: Short use only. Chinese practice uses it for a bleeding episode, not as a daily tonic. If bleeding has not settled within a few days, stop and see a doctor. Do not keep using it for weeks to mask bleeding whose cause is unknown.