Cangzhu and Huangbai are the constituent medicines of Ermiao San. The combination of Atractylodes macrocephala and Phellodendron Bark is mainly used for the treatment of tendon and bone pains, impotence and weakness of feet, redness, swelling and pain of feet and knees caused by dampness-heat infiltration (the invasion of dampness and heat into the intestines, bladder, pubic region and lower limbs), damp-heat subluxation, and wet sores in the lower part of the body. Cangzhu has the effect of drying dampness, strengthening the spleen, dispelling wind and dispersing cold, and brightening the eyes. It can be used to treat dampness obstructing the middle jiao (dampness obstructing the function of the spleen and stomach), epigastric (abdominal) distension, diarrhea, edema, impotence of the feet and limbs (weakness of the lower limbs), and rheumatism and paralysis pains. It is not to be taken by those who are suffering from Yin deficiency, internal heat, Qi deficiency and excessive sweating. Phellodendron Bark has the efficacy of clearing heat and drying dampness, removing fire and steam, detoxifying and healing sores, and can be used to treat damp-heat diarrhea (diarrhea caused by feeling damp-heat), jaundice and urine redness, vaginal itching under the belt, feverish gonorrhea (burning and tingling pains in urination, accompanied by urinary urgency, discomfort in the abdominal region) and astringent pains, and bone vaporization and laborious heat. Spleen deficiency and diarrhea, weak stomach with little food should not be taken. The two herbs are used together, bitter, cold, warm and dry phase control, long in the lower focus. Therefore, if the dampness and heat downstream caused by the tendon pain, impotence and weakness of the feet, feet and knees, red, swollen and painful, dampness and heat under the belt, the lower part of the wet sores, etc., can be combined with Cangzhu, Huangbai treatment. In addition, Chinese medicine is concerned about the identification of the use of medicines, such as the need to match the use of Chinese herbs, should be under the guidance of the doctor’s identification.