In fact, Radix Rehmanniae is not pure white. The root tuber of Radix Rehmanniae of Scrophulariaceae is red and yellow in color, especially when it is freshly unearthed. Because of this color, people in the world named it Rehmanniae. Fresh products can be directly used as medicine after washing, or dried in the sun, or steamed for nine times and dried for nine times, but rare users are used to calling them "fresh rehmannia root" or "raw rehmannia root", and the habit of drying in the sun is called "raw rehmannia root" or "dried rehmannia root" [1]. After steaming for nine times and drying for nine times, Rehmannia root is naturally prepared.
Fresh rehmannia glutinosa and dried rehmannia glutinosa have the same taste, both of which are sweet, bitter, cold, sweet and nourishing yin. Rehmannia glutinosa is a commonly used product for nourishing yin, and it has been a traditional Chinese medicine often used by doctors from Zhang Zhongjing's time to the prevalence of epidemic febrile diseases in Ming and Qing Dynasties. Moreover, Rehmannia glutinosa can not only replenish the yin of various organs, such as heart, liver and kidney meridians, but also cool blood, so it returns to heart, liver and kidney meridians.
Rehmannia glutinosa is cold and good at entering blood, which has three functions, namely, cooling blood, nourishing yin and stopping bleeding [1][2], but many people don't know it.
1. Clearing heat and cooling blood
Rehmannia glutinosa has excellent blood cooling effect, and it is the first drug to cool blood, and it is mainly used for blood heat syndrome, including warm disease and heat evil entering the interior deeply (in nourishing blood) and blood heat of miscellaneous diseases. Fever due to epidemic febrile diseases often aggravates at night, dry mouth is obvious, and the tongue is red without coating. Rehmannia glutinosa is often used in the treatment with Scrophularia and Lonicera japonica (Ye Tianshi recorded it in Treatise on Warming), such as Qingying Decoction; If the heat pathogen is deeper and has entered the blood, it is often seen that patients are dizzy, have a crimson tongue, have abnormal bleeding (such as vomiting blood and bloody stool), and have dark spots. Rehmannia glutinosa is often combined with drugs such as buffalo horn, red peony and peony bark, such as Liangxue Dihuang decoction. Blood-heat of miscellaneous diseases is that there is no obvious exogenous pathogen invading the human body, but there is a disease. This situation is generally mixed with excess and deficiency of the body. For example, psoriasis and eczema in skin diseases have a long course of disease, and the condition is repeated, and qi and blood are often stagnant and turn into fire. If there is a blood-heat phenomenon, doctors will choose Radix Rehmanniae to join the compound prescription to clear the heat and calm the blood.
2. Cool blood to stop bleeding
"The Theory of Medicinal Properties" points out that Radix Rehmanniae is "the main cause of hematemesis", and Zhang Zhongjing often uses Radix Rehmanniae to achieve effect in bleeding diseases. After careful study, it can cool blood and then stop bleeding, eliminating bleeding movement and thus achieving the effect of stopping blood. Both raw and fried charcoal have this effect, but the hemostatic effect is more obvious after fried charcoal, because the astringency of the medicine after fried charcoal is more astringent. Because of the use of traditional Chinese medicine compound, the cooperation of various drugs makes the hemostatic scope of Radix Rehmanniae wider. For example, Sisheng Pill can treat hematemesis and epistaxis (nosebleed) caused by blood heat. Huangtu decoction can treat gastrointestinal bleeding due to deficiency and cold of spleen and stomach; Xiaoji Yinzi can cure hematuria caused by blood-heat rash, and so on.
3. Nourishing Yin and Producing Body Fluid
Although Rehmannia glutinosa does not belong to Yin-nourishing medicine, it has a strong Yin-nourishing effect and a wide range of applications, especially fresh Rehmannia glutinosa. If it is not dried, its juice is very rich. If it is mainly used to nourish Yin and produce body fluids, ancient physicians often use fresh products, and the dosage is large, as Zhang Xichun did in "Medical Enthusiasm", and there are many detailed cases. If it is yin deficiency with internal heat and bone steaming with hot flashes, it can be used equally with Anemarrhena asphodeloides and Cortex Lycii. In the late stage of epidemic febrile disease, it can be used with herbs such as Artemisia annua and Carapax Trionycis. If constipation due to yin deficiency and intestinal dryness is obvious, you can use the famous liquid-increasing soup, which contains Radix Rehmanniae, Radix Scrophulariae and Radix Ophiopogonis, and it is easy to defecate by increasing water.
However, it should be noted that Rehmannia glutinosa is cold and greasy, and it should not be used by people who are wet with water. If the condition requires it, the amount will not be endless, at most, it will be between10 ~15g. If it is fresh Rehmannia glutinosa, the juice will be more, and the dosage will be between12 ~ 30g. Because Radix Rehmanniae has obvious laxative effect, people with loose stools also need to use it with caution. The same is true of Radix Rehmanniae Preparata. In order to reduce the influence of nourishing on Qi-moving, physicians often add qi-moving drugs such as Amomum villosum to the recipe, or stir-fry Radix Rehmanniae Preparata and Amomum villosum. The best way to keep healthy is to keep qi flowing smoothly and keep the viscera and qi moving normally.
References:
[1] Wang Jian, Wang shiyuan. traditional Chinese medicine [M] Beijing: China traditional Chinese medicine press, 20 15.
[2] Ling Yikui. Chinese Medicine [M]. Shanghai: Shanghai Science and Technology Press, 2005.