Educational information, not medical advice — ask your doctor or midwife.
Da Suan is garlic: the bulb of the plant Allium sativum. It is both a food and a single herb in Chinese medicine. There it is classed as warm and pungent.
In that tradition it is given for cold-type gut problems and for parasites (tiny pests that live in the body). Put on the skin, it is used for rashes and fungal problems. Today most people take it for heart health.
The evidence verdict: garlic has a long, wide record of traditional use. Human trials point to small but real effects on blood pressure and blood fats.
Those effects are modest, and the trials are mixed in quality. Standing in tradition and proof of effect are two different things. A long history of use does not by itself show that something works.
Garlic is safe as a food for most people in normal cooking amounts. Strong supplements are another matter. They thin the blood a little, and they clash with several prescription drugs.
Garlic's effects are thought to come from sulphur compounds. These form when you crush or chop a clove.
The compounds seem to relax the walls of blood vessels. That may explain the small drops in blood pressure seen in trials.
They also make platelets slightly less sticky. Platelets are the tiny cell bits that form clots. This is why bleeding risk goes up with drugs that act the same way.
In the lab, garlic also kills bacteria and fungi. Whether that treats an infection in a person is not known. Do not rely on it for one.
Common forms include:
- Fresh raw cloves, crushed and eaten, or added to food at the end of cooking - Cooked garlic in food, which loses much of the allicin - Dried garlic powder in tablets, often coated to cut the smell - Aged garlic extract, taken as capsules or liquid - Garlic oil softgels - Garlic in TCM decoctions and pastes, sometimes put on the skin
Garlic is one of the oldest recorded medicines in the world. It appears in Egyptian, Greek, Roman, Indian and Chinese sources.
Workers and soldiers were fed garlic as a tonic. That was long before anyone knew what was in it.
Chinese medicine records Da Suan as warming the middle burner (the digestive centre). It is also said to move stuck food, kill parasites and dry damp skin problems.
It has stayed in daily use in kitchens and clinics in many cultures. That run of use goes back well over two thousand years.
See a doctor promptly if you notice unusual bruising, nosebleeds that will not stop, blood in your urine or stool, or black tarry stools while taking garlic.
Get emergency help if you have swelling of the lips, face or tongue, a spreading rash, or trouble breathing after taking garlic; that can be a severe allergic reaction.
Also see a doctor if raw garlic on your skin has caused a burn or blister, if you are relying on garlic for high blood pressure instead of prescribed treatment, or if you have a suspected parasite or infection that needs proper diagnosis.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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