Cang Er Zi is generally used for internal use, not for external use or boiled water foot soak, and external use is not as effective as decoction of internal use, it is recommended that patients who need to consult a medical professional. Cang Er Zi is pungent, bitter, warm, slightly toxic, and belongs to the lung meridian. It has the efficacy of dispersing wind-cold, clearing the nose, dispelling wind-dampness and relieving pain. Cang Er Zi is commonly used in the clinical treatment of wind-cold headache, nasal congestion, runny nose, congested nose, nasal abyss (mainly manifested as obscene nasal mucus, the amount of wiping unclean), wind rash, itching, dampness paralysis contracture. Cang Er Zi is poisonous, should not be taken internally in excess, and can not be taken continuously; Cang Er Zi disperses qi and consumes blood, and should be used with caution by those who are physically weak. Cang Er Zi is generally not used externally, it is recommended that patients in need of timely medical treatment, under the guidance of a doctor.