Erythromycin ointment is an antibiotic drug whose main function is to treat skin infections, inflammation, acne and other problems. Its specific functions are as follows:

1. Antibacterial effect: Erythromycin ointment can kill bacteria on the skin, including Gram-positive bacteria and Gram-negative bacteria and other common bacteria.

2. Anti-inflammatory effect: Since skin infections and inflammation are sometimes caused by bacteria, the antibacterial effect of erythromycin ointment can also play a certain anti-inflammatory effect.

3. Control acne: Erythromycin ointment can also be used to treat acne, which can reduce the number and inflammation of acne.

In short, the main functions of erythromycin ointment are antibacterial, anti-inflammatory and acne treatment. When using it, it should be used correctly according to the advice of your doctor.