Primarily, rehmannia is the number one most important herb in the Chinese system for disorders related to the kidneys and adrenal glands. According to TCM, kidney imbalances can cause weakness in the legs and lower back, and also hearing loss. Because rehmannia is used to restore adrenal function and purify the kidneys, it is considered a helpful tonic for these conditions.
Rehmannia is said to ‘cool down internal heat’ and help decrease blood pressure.
In Asia, it is often used as a helpful tonic for the liver, kidney, and heart, and to treat many other ailments, such as anemia, diabetes, constipation, dizziness, urinary incontinence, and for women experiencing menopause, hair loss, irregular menstrual cycles, and other hormone deficiencies.
Another modern day problem—blood sugar balance—can also be helped by regular use of rehmannia.