(shu di huang or sheng di huang)
What is rehmannia? What is it used for?
Rehmannia is a perennial herb indigenous to China, Japan and Korea. It grows to a height of approximately 18 inches, and contains alternating leaves with reddish-violet flowers. The root tuber is used medicinally.
In traditional Chinese medicine, rehmannia is used as a diuretic and to strengthen the kidney, liver and heart. Fresh and dried forms of rehmannia tuber are used differently. Fresh root tuber is used on the liver and kidney meridians for conditions such as irregular menstruation; lowered immunity; insomnia; tinnitus; vertigo; impaired hearing; diabetes; and frequent urination. Dried tuber is used mainly for fevers and fever-related conditions; dry mouth; nosebleeds; internal bleeding; rheumatism; and constipation.
How much rehmannia should I take?
As a decoction, many practitioners recommend taking between 9-15 grams of rehmannia. It can also be taken as part of a rice wine.
What forms of rehmannia are available?
Whole rehmannia tuber is available in either fresh or dried forms. Rehmannia powder is sold at some Asian markets and specialty stores.
What can happen if I take too much rehmannia? Are there any interactions I should be aware of? What precautions should I take?
As of this writing, there are no known adverse reactions or drug interactions with rehmannia. Rehmannia is considered safe as long as it is taken within recommended therapeutic doses.
Bensky D, Gamble A. Chinese Herbal Medicine, Materia Medica. Seattle, Washington: Eastland Press Incorporated, 1993.
Kubo M, Asano T, Matsuda H, et al. Studies on rehmanniae radix. III. The relation between changes of constituents and improvable effects on hemorheology with the processing of roots of rehmannia glutinosa. Yakugaku Zasshi February 1996;116:158-68.