Ermu San is composed of Bei Mu and Zhi Mu. For each dose of five qian, it is necessary to add two cups of water and three slices of ginger. This medicine is effective in nourishing Yin, clearing the lungs, relieving cough and resolving phlegm. Ermu San is a Chinese herbal formula composed of Bei Mu (贝母) and Zhi Mu (知母), in which Bei Mu (贝母) can clear heat and moisten the lungs (clearing away heat to nourish the lungs), resolving phlegm and stopping cough, while Zhi Mu (知母) can clear lungs and fire and nourish yin and moisten dryness (nourishing the yin essence and clearing away heat), which makes Ermu San nourishing yin and clearing away heat to clear away phlegm and stopping cough. When Ermu San is used, for every five qian used, two jian of water and three slices of ginger should be added. Ermu San is used for conditions such as congestion of phlegm and saliva (abnormal phlegm and excessive production of saliva), consumptive lungs with fever, cough and wheezing. This medicine is cold in nature and needs to be contraindicated for people with cold lungs and cough. If wheezing is severe, add Bitter Drabanemerosa hebecarpa (Draba hebecarpa). The specific use of Ermu San must strictly follow the doctor’s instructions, do not self-medicate.