“Good at curing phlegm outside the skin and membrane” is a description of white mustard, not a description of Chinese medicine prescription. The basic effect of white mustard seed is to warm the lungs, expel phlegm and promote qi, dispersing knots and relieving pain. White mustard seed pungent dispersing warm through, specializing in opening the knot phlegm, “phlegm in the skin outside the membrane, not this does not reach”, for cold condensation and phlegm stagnation of the yin gangrene (is a class of slow condition of yin sores and ulcers of the disease of the general term), diffuse swelling without head, pain and soreness without heat, and wet phlegm flow (hair in the muscle deep multiple abscess) meridian of the limbs of the numbness, joints and pain. White mustard seed main into the lung meridian, can dispel chest and diaphragm cold phlegm, suitable for cold phlegm congestion lung cough asthma, phlegm more clear thin, etc., can be used with Laptopus and perilla seeds. This product has foaming effect on the skin, skin ulcers or allergies should not be applied externally. Lung deficiency and chronic cough and yin deficiency and fire are cautious; qi and yin deficiency and bleeding tendency is contraindicated. Adverse reactions are not clear. Patients who are not feeling well are advised to consult a doctor in time, and the drug needs to be used under the guidance of a doctor, not blindly.