When the acute symptoms of a respiratory tract infection disappear, the cough persists. In addition to respiratory viruses, other pathogens such as bacteria, mycoplasma and chlamydia can cause post-infection cough. Treatment of post-cold cough: (1) Antibacterial medication is ineffective. (2) For some chronic prolonged coughs, central cough suppressants and antihistamine H1 receptor antagonists can be used for a short period of time. (3) For a few patients with intractable severe post-cold cough, if general treatment is ineffective, a short-term trial of inhaled or oral glucocorticoid therapy, such as 10-20 mg of prednisone for 3-7 days, can be used. Post-cold cough is mainly dry cough with no sputum, or a small amount of white mucus sputum, unpleasant sputum, sometimes with mild wheezing, itchy pharynx, dry pharynx, coughing at night, triggered or aggravated by cold air, dusty environment, irritating gas, exercise, smoke, etc. Some of the patients have chronic congestion in the pharynx and hyperplasia of lymphatic follicles in the posterior wall. The treatment is to clear and moisten the lung, to relieve cough by relieving phlegm. The medicine includes 6g of roasted ephedra, 10g of bitter almonds, 10g of northern sage, 10g of burdock, 10g of roasted aster, 6g of orris, 10g of zhebei mum, 10g of roasted loquat leaf, 10g of cicada, 5g of raw licorice, 6g of Chuanbei mum, etc. If the cough is prolonged without sputum and the pharyngeal itch is more severe, add Sclerotium, Wu Mei, Wu Wei Zi, etc.; if the sputum is less easy to cough out, add Han Xia, Orange Red, etc. If you are sensitive to cold air and irritating odor, you can add Fangfeng, Hooked vine, etc. If the cough leads to pain in the joints, and the cough is aggravated, add green peel, heliotrope, aromatic herb, yanghusuo, etc., as appropriate, to dredge the liver and relieve pain; if the cough leaves drowning, add qiangwu, chebuli, etc., as appropriate.