The whole root of the plant is used to make tinctures and capsules.
Its popularity is based on its effects as a women’s tonic. It is called "female ginseng".
It contains iron, vitamins A, B12 and E as well as muscle-relaxing compounds.
Evidence of its effectiveness has not been shown in modern trials, but centuries of use in Japan, Korea and China must count for something.
Women use Dong Quai to treat disorders such as premenstrual syndrome, menstrual cramps and to help them get over the menopause. You will often find it in combination with other herbs for these purposes.
It has also been used for anaemia, migraines and cardiovascular problems.
The accepted dose in capsule form is 1 to 2 grams taken three times a day.
Side effects are rare, but occasional sensitivity to sunlight can happen, especially if you are fair-skinned. This causes inflammation and skin rashes that can be controlled by using sunscreens and staying out of direct sunshine.
Do not take Dong Quai during pregnancy or if you are taking anticoagulants or blood thinning drugs such as warfarin or aspirin.
In theory, there could be a problem using Dong Quai along with other herbs that also have blood-thinning actions. So, avoid combination of Dong Quai with feverfew, garlic, ginseng, ginkgo biloba, liquorice and turmeric just in case they lengthen your blood clotting time.
Dong quai may make heavy menstrual bleeding worse.