Can raw rehmannia (sheng di) be steeped in water and consumed long-term?

Generally, it is not recommended to regularly consume raw Rehmannia (Sheng Di) by steeping it in water. The use of herbal medicines should follow medical advice. Specific analysis is as follows:

Raw Rehmannia, also known as Sheng Di Huang, is a commonly used traditional Chinese herb with various therapeutic effects, including clearing heat and cooling the blood, nourishing yin, and promoting body fluid production. Because of its function in nourishing yin and promoting fluid production, raw Rehmannia has a tonifying nature. According to Traditional Chinese Medicine (TCM), yin and yang can transform into each other. Long-term consumption of raw Rehmannia tea may lead to excessive yin-nourishment, resulting in "heatiness" symptoms such as nosebleeds, red and swollen gums. Raw Rehmannia is cold in nature; prolonged intake of cold and cooling herbs may impair the spleen and stomach, disrupting their digestive and transformation functions, potentially causing spleen deficiency with loose stools, abdominal pain, bloating, or diarrhea. Although herbal medicines generally have fewer side effects, long-term consumption of raw Rehmannia tea may increase the metabolic burden on the liver and kidneys, and could even lead to liver or kidney damage.

Despite its multiple medicinal benefits, long-term consumption of raw Rehmannia tea is not advisable. When using raw Rehmannia, dosage should be adjusted according to individual constitution and medical condition, avoiding excessive or prolonged use to prevent adverse effects.