The severity of lung nodules is generally not determined by whether they are single or multiple, but depends mainly on whether the nodules are benign or malignant in nature. 1. Benign lung nodules: either single or multiple nodules may be benign nodules, which can be lung inflammation, tuberculosis, misshapen tumors, lipomas, etc. They can be treated with surgery, anti-infection treatment and regular follow-up. 2. Malignant lung nodules: i.e. lung cancer, can be single or multiple lung nodules, which are more serious and need to be treated with surgery or radiotherapy in time. It is recommended to communicate with the attending physician for further clarification of the condition after finding lung nodules.