Cough aggravation on the third day of coughing usually indicates that the disease is progressing and needs to be treated aggressively, and is not a normal phenomenon. The worsening of the cough on the third day of coughing is often a sign of a change in the condition of the disease, either because of an aggravation of the existing disease or because of a possible combination of other diseases. Examples are as follows: 1. Pneumonia: generally no symptoms or mild symptoms in the early stage, manifested as coughing, coughing up sputum, with the progress of the original respiratory symptoms will be aggravated, or the emergence of a violent cough, coughing up purulent sputum or bloody sputum, with or without chest pain, fever and so on. Large lesions can have dyspnea, respiratory distress. 2. Colds: Colds are caused by viral infections, mainly nasal congestion, runny nose, sneezing, sore throat, coughing, coughing up a small amount of sputum, and thickening of nasal mucus. When the cold condition worsens or is combined with a bacterial infection, coughing and sputum worsening can occur. Cough aggravation on the third day is recommended to go to the regular hospital in time to improve the relevant examination to identify the cause, give targeted treatment or treatment.