Cold is a general term for upper respiratory tract infections, mainly caused by cold, rain, fatigue and other reasons for the body to reduce resistance, which induces the outside world or the host in the nasal mucosa, pharynx, oral cavity of viruses, bacteria, mycoplasma, chlamydia, rickettsiae and other pathogens in large numbers of invasion of the body, so that the mucous membrane of the upper respiratory tract appeared to be congestion, edema, as well as inflammatory substances exudate inflammatory reaction, exudate contains a large number of living and dead pathogens, shedding tissue debris and metabolic products of the inflammatory reaction. The exudate contains a large number of living and dead pathogens, detached tissue fragments and metabolic products of the inflammatory reaction. The patient will have the corresponding clinical manifestations, such as nasal congestion, runny nose, sneezing, coughing, sputum, watery eyes, accompanied by fever or even a state of high fever, as well as headache, muscle aches and pains. Most common colds do not require special treatment. By drinking plenty of lukewarm water, resting and keeping warm, these symptoms will slowly subside and disappear, and can be completely cured within a week. Some severe upper respiratory tract infections require necessary medical intervention and anti-inflammatory treatment.