In general, thick sputum after a cold is mostly indicative of a bacterial infection that is difficult to heal on its own. The most common symptoms in patients with colds are sneezing and runny nose, which can appear as clear nasal discharge and eventually progress to pus nasal discharge, but rarely cough up sputum. If a virus causes a lower respiratory tract infection, viral pneumonia also rarely has coughing sputum. Patients who develop pus sputum after a cold need to pay attention to whether there is a secondary bacterial infection, and it is best to go to the hospital for routine blood tests. If the routine blood leukocytes and neutrophils are elevated, it indicates bacterial infection, and antibacterial drugs should be applied to treat it. Therefore, patients with pus sputum after cold must go to the hospital for examination, and it is better to do a chest CT or X-ray examination to clarify whether there is bronchitis or pneumonia. If you do not go through these tests and wait for the condition to heal on its own, it may delay the condition. Patients with colds are advised not to stay up late and to get enough sleep to recover their strength. Do not smoke, do not drink, and develop good habits. You should eat foods rich in water, vitamins and protein, such as fresh vegetables and fruits. Do not go to places where people gather to prevent the transmission of cold virus.