Coughing is a protective reflex and a clinical symptom of many diseases, especially seen in respiratory diseases. A cough can be either sputum or non-sputum, and there are certain differences between the two: 1. The concept is different, as a cough with sputum is called a wet cough and a cough without sputum is called a dry cough. 2. A dry cough can be seen in both respiratory and non-respiratory diseases, such as heart disease and central diseases. A dry cough is usually not associated with infection, while a wet cough is often associated with infection, such as infection with bacteria, viruses, mycoplasma, chlamydia, etc. 4. A dry cough is often associated with non-specific inflammation, such as bronchial asthma and chronic bronchitis, while a wet cough is often associated with infectious inflammation. 5. Dry cough can be treated with powerful cough suppressants, while wet cough is mostly treated with expectorant treatment without cough suppression.