Rehmannia: A Chinese Mystery

When it comes to traditional Chinese medicine, the key to good health is maintaining the balance between the two opposing forces in your body: yin and yang. But what happens when the yin is unbalanced? With rehmannia, you may never need to know.

According to practitioners of traditional Chinese medicine, rehmannia (a wild herb also known as Chinese foxglove) can “balance the yin.” The herb grows in parts of northern and northeastern China, and has been used in medicine for over 2,000 years. Its thick brownish-black roots are usually harvested in the fall and used for a variety of medical purposes. It’s commonly used to treat conditions believed to be caused by yin deficiency. These include a whole host of complications, including: allergies, anemia, cancer, constipation, diabetes, fever, eczema, high blood pressure, bacterial and fungal infections, rheumatoid arthritis, osteoarthritis, insomnia, and pain relief.

Scientific Evidence Is Scant

Traditional Chinese medicine is based on the belief in opposing forces, energy flow, and the five elements of earth, fire, metal, wood, and water. However, while ancient medicine holds rehmannia in high regard, modern research has yet to produce scientific evidence for its effectiveness at treating any medical conditions.

It’s common for traditional Chinese remedies to include a combination of herbs, be they in pill, liquid, powder, or tea form. This means that, while rehmannia is a common ingredient, it’s hard to tell whether it’s the combination or the specific herb that’s producing results. Traditional Chinese herbal remedies are also made for each individual based upon his or her particular needs. The Chinese herbal remedies that people receive tend to vary with each person.

Additionally, when it comes to study of individual Chinese herbs, most research is still in very early stages. Often, only animal studies have been done or human studies are too small to determine effectiveness. However, research is ongoing. One 2013 study found that catalpol, a chemical in rehmannia, might be able to prevent cell death caused by neurodegenerative disorders.  

Are There Side Effects?

So far, side effects such as nausea, gas, diarrhea, headache, heart palpitations, dizziness, vertigo, allergies, and fatigue have been reported. Rehmannia may also be unsafe for people who have liver disease or pre-existing digestive or immune issues. It is not considered safe for children or pregnant or breastfeeding women. There have been reports of Chinese herbal products being contaminated with other potentially dangerous substances.

Chinese herbal medicines are sold in the United States as supplements. Because they are not regulated by the U.S. Food and Drug Administration (FDA), there is no recommended dose. Supplements usually contain anywhere between 55 to 350 milligrams (mg).

If you choose to try traditional Chinese medicine, it’s important to know that the U.S. doesn’t have national regulations or required qualifications for complementary health practitioners. Each state has different criteria. In order to make sure you get quality care, check to see what licenses, certifications, or credentials are required in your state. You can also ask about the person’s education and training.

For now, there’s no scientific evidence to back the claims about rehmannia up, but future research may change that. Chinese herbal medicines should not be used as a substitute for conventional medical treatment, and you should discuss any alternative treatments with your doctor.