The difference between ripe dihuang and raw dihuang is mainly in the three aspects of flavor and attribution, efficacy and main treatment, and precautions. 1. Taste and Meridian: Radix Rehmanniae Praeparata has a sweet, slightly warm flavor and goes to the liver and kidney meridians; Radix Rehmanniae Praeparatae has a sweet, cold flavor and goes to the heart, liver and kidney meridians. 2. Effects and Indications: Radix Rehmanniae Praeparata tonifies blood and nourishes yin (nourishes blood and nourishes yin), benefits essence and fills the marrow (nourishes essence and fills the marrow). It is mainly used in treating blood deficiency and yellowish color (deficiency of blood leading to a yellowish color of the face), menstrual disorders, lumbar and knee soreness and tenderness (feeling of soreness and weakness of the lumbar and knee areas), night sweating (sweating abnormally after falling asleep, but sweating stops after waking up), spermatorrhea, deficiency of the liver and kidney (weakness of the liver and kidneys), deficiency of essence and blood, vertigo Tinnitus; Sheng Di Huang clears heat and cools blood (relieving blood heat by clearing heat), nourishes yin and generates fluids (nourishing yin fluid while transforming fluids), and is mainly used in the treatment of temperature-poisoned macules (warm-heat poisonous evils invading the body resulting in blotchy, patchy skin), bleeding from blood-heat, heat illnesses that injure the yin, yin deficiency that causes heat and fluid injuries that result in constipation. 3. Precautions: Both for spleen deficiency and dampness stagnation, abdominal fullness and loose stools (feces sparse and not shaped) should not be used, but cooked dihuang, if reused for a long period of time, it is advisable to use with Chen Pi, sand nuts, etc., so as not to nourish and impede the stomach. It should be noted that both raw dihuang and cooked dihuang dosage need to be decided by a professional doctor, the patient can not increase the dosage without authorization in order to avoid causing adverse reactions.