Rehmannia, known by the Latin scientific name of "rehmannia glutinosa" and commonly referred to as "Chinese foxglove", is a perennial herb that grows in China, Japan and Korea. Its roots have a viscous texture, which gave the "glutinosa" (glutinous) part of the plant's scientific name, and they are a popular remedy in traditional Chinese medicine. Rehmannia is generally known to be safe for use by people.
Effects
Rehmannia has immunosuppressive, antibacterial, antihepatotoxic and anti-inflammatory effects. According to the PDR for Herbal Medicines, clinical trials have proved the plant's efficacy in the treatment of diseases like rheumatoid arthritis, eczema and hepatitis.
Forms
Rehmannia can be used in raw form, where the root is harvested in the fall, cleaned and cooked. A second mode of use is cutting, steaming and then drying the root until it loses 80% of its humidity. It can also be found on the market in powder and pill form, as a single herb or present in formulations that include more herbs.
Uses
Rehmannia has historic known uses in the treatment of diseases that cause heat related symptoms such as sweating, fever, inflammation, bleeding, dryness and thirst.
The fresh and dried forms are used for different conditions. The fresh rehmannia remedy is considered efficient for weak liver and kidney, for raising immunity to deal with allergies and for regulating menstruation. It is also recommended in cases of insomnia, vertigo, diabetes, hearing problems, excessive sweating and frequent urination. In dried form the remedy is used for fever, dry mouth, bleeding, rheumatoid arthritis, constipation hepatitis and diabetes. Presently, in China, rehmannia is used mainly as ingredient in women's menstruation tonics and in treating hormonal disorders.
Adverse Reactions
When used in the proper, recommended dosage and for short periods of time (not more than four months) rehmannia remedies are not known to have adverse reactions. There are rare cases, though, when mild side effects like abdominal pain, diarrhea, dizziness, hypoglycemia, palpitations, fever and hemorrhage have been experienced.
According to the National Standard, a research collaboration enterprise working in the field of complementary and alternative therapies, "it is hard to differentiate what side effects are caused by rehmannia alone, because it is so frequently used in combination with other herbs".
History
In China rehmannia is known as "dihuang", which means "earth yellow" or "disui", meaning "earth marrow". In the Shen Nong Ben Cao Jing, translated as "The Divine Farmer's Materia Medica," one of the foundation books of the traditional Chinese medicine, rehmannia is described as a sweet and cold herb that promotes growth of the bone marrow and muscle and its extended use is said to help prevent senility.
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