Considered by many as the "woman's herb", Dong quai (Angelica sinensis) is native to China where some consider it the female tonic as ginseng is the male tonic (a drastic over-simplification of traditional Chinese medicine). The dried roots have coumarins, flavonoids, and essential oils as active constituents. Many of dong quai's activities were thought to be due to its phytoestrogenic activity. In recent years researchers have failed to confirm any phytoestrogenic activity associated with dong quai or its extracts. This fact does not decrease it ability to act as a uterine tonic as it increases relaxation of smooth muscles.

The coumarin levels in dong quai are potentially blood-thinning, and have also been known to block calcium channels. These activities make dong quai a mild hypotensive, and may account for its smooth muscle relaxing activity. Some women find that the use of dong quai during menstruation increases bleeding, and this should be monitored.

Extracts of Angelica sinensis roots are usually 4:1 or standardized to contain between 0.8% and 1% ligustilide (a volatile oil). Women should consult a qualified individual before taking Dong Quai if they are pregnant or are unsure of the cause of their mestrual discomfort.