Rehmannia glutinosa can be divided into Rehmannia glutinosa and Rehmannia glutinosa. Compendium of Materia Medica records: Rehmannia glutinosa is very cold, but it is needed by those with blood cold and blood heat, and it is cooked slightly warmer, but it is needed by those with kidney deficiency and blood failure. Men with more yin deficiency use Radix Rehmanniae Preparata, and women with more blood heat use Radix Rehmanniae. Especially Radix Rehmanniae Preparata, is used for filling marrow and promoting granulation. It is really a good product to nourish the five internal organs, benefit the eyes and ears, blacken the hair and promote blood circulation. Both Rehmannia glutinosa and Rehmannia glutinosa are the roots of Rehmannia glutinosa, a perennial herb of Scrophulariaceae. Due to different processing methods, its properties and clinical application are also different. Rehmannia glutinosa, also known as dried rehmannia glutinosa, is sweet, bitter and cold. It has the effects of clearing heat and cooling blood, nourishing yin and promoting fluid production, and is a medicine for clearing heat and cooling blood. Can be used for the symptoms of febrile diseases, such as heat entering the blood, body heat, dry mouth, crimson or red tongue, such as Qingying decoction; For hematemesis, hematuria, metrorrhagia and metrorrhagia caused by blood heat, such as Sisheng Pill and Rhinoceros Horn Dihuang Decoction. It can be used for symptoms such as fever, yin injury, dry tongue, thirst or polydipsia, and diabetes, such as Yiwei Decoction and Yuquan Powder. In addition, it can also be used for constipation caused by heat-induced intestinal dryness, such as zengye decoction. The usual dosage is 10g~30g ~ 30g. Radix Rehmanniae is cold and stagnant, so it is not suitable for people with spleen deficiency and dampness resistance and full stomach and loose stool. Rehmannia glutinosa is prepared from wine, Fructus Amomi and Pericarpium Citri Tangerinae. After repeated steaming, Rehmannia glutinosa turns black inside and outside, and it is oily and soft. Sweet in taste and warm in nature, it has the effects of nourishing blood, nourishing yin and replenishing essence, and is an important drug for enriching blood. For blood deficiency, chlorosis, dizziness, palpitation, insomnia, irregular menstruation, metrorrhagia, etc., such as Siwu Decoction, the basic prescription for tonifying blood and regulating menstruation; For deficiency of kidney yin, hot flashes, night sweats, nocturnal emission and thirst-quenching, such as Liuwei Dihuang Pill. In addition, Radix Rehmanniae Preparata is also effective for various syndromes of deficiency of essence and blood, such as backache and leg weakness, dizziness, tinnitus and deafness, and premature gray hair. The usual dosage is 10g~30g ~ 30g. Because the nature of Radix Rehmanniae Preparata is thicker, worse than Radix Rehmanniae, and it interferes with the digestive function, people who suffer from qi stagnation and phlegm, abdominal distension and pain, and eat less loose stool should not take it. This product should be taken together with spleen-strengthening and stomach-strengthening drugs such as tangerine peel and Amomum villosum. There are dried rehmannia glutinosa and fresh rehmannia glutinosa, which can clear away heat and cool blood, but fresh rehmannia glutinosa has strong heat-clearing effect and can produce fluid; The difference between them is that dry land has a strong function of nourishing yin. Stir with Radix Rehmanniae and yellow wine, and steam until black, that is, Radix Rehmanniae Preparata.