From the Manufacturer:
Dong quai has been an important element in traditional Chinese medicine for several thousand years. Also called “female ginseng” it is the second most popular herb in China today. It is also one of the most thoroughly researched Chinese herbs. In China, dong quai is considered a woman’s herb helping regulate the menstrual cycle and ease menstrual pain.
Research reveals that dong quai contains compounds that in lab tests demonstrated some capacity to reduce pain, dilate blood vessels, and both stimulate and then relax the uterus. Dong quai contains ferulic acid, a compound capable of relaxing muscles and reducing pain. These compounds may account for dong quai’s reported ability to ease menstrual pain and other discomforts like PMS. Dong quai is also useful for restoring regularity to cycles after ceasing use of the birth control pill.