Chinese medicine considers cold evil to be an evil with cold and condensation characteristics, so the pathogenic characteristics of cold evil and its nature can be divided into the following points: 1. Cold evil is a yin evil and tends to injure the yang energy in the body, so the yang energy is damaged and the organism loses warmth. The clinical symptoms are mostly associated with heavy vicious cold, light fever, coughing, coughing and thin sputum, and if the cold evil injures the spleen and kidneys, it leads to abdominal pain, cold body and limbs, weakness of the waist and knees or cold pain, etc. 2. cold evil stagnates, when the cold evil attacks the body, it shows that the qi and blood are condensed, stagnant and blocked, and the nature of pain appears, such as the cold evil stagnates the heart and chest and shows the heart and chest suffocation, pain, and a feeling of tightness. 3. cold attracts. When the external cold evil is sensed, it shows the nature of collection and attraction and constriction, such as the cold evil stagnates the meridians and manifests joint constriction, pain and unfavorable flexion and extension, and at the same time, it has the characteristics of preferring warmth and pressure.