Xuan Shen is cold in nature and should not be used by people with coldness in the spleen and stomach (spleen and stomach weak and cold), or with loose stools (thin and unformed feces), nor should it be used with quatrefoil. Xuan Shen has the efficacy of nourishing yin and lowering fire (nourishing yin essence and lowering fire), clearing heat and cooling blood (relieving blood heat by clearing heat), and detoxifying and dispersing toxins and nodules. It can be used for warm poisonous spots (warm and hot poisonous evils invading the human body resulting in spots and plaques on the skin), bone vaporization and laborious coughing, constipation due to injury of the fluids, sore throat, carbuncle and swollen poisons, swelling and pain of redness in the eyes, and scrofula (mainly refers to tuberculosis of lymph nodes of the neck), and other symptoms. Xuan Shen can also be used for heat entering the camp blood (the degree of invasion of heat into the body is deep and the symptoms are more serious), symptoms such as heartburn and thirst, body heat at night, red tongue and number of veins, etc. It is often used in combination with Salviae Miltiorrhizae, Radix Rehmanniae Praeparatae and Forsythiae Miltiorrhizae. Patients should not use medicines by themselves and should go to the hospital as soon as possible if they feel unwell.