Gramicidin is a topical antibiotic that is used to treat certain skin infections that are caused by gram-positive bacteria. Gramicidin is commonly included with other antibiotics in combination antibacterial ointments for topical use.

Gramicidin is a mixture of several closely related antibacterial molecules, Gramicidin A, Gramicidin B and Gramicidin C.

Gramicidin containing ointments are occasionally used as topical treatments for acne symptoms. The acne-causing P. acnes bacterium appears to have some natural resistance to this antibiotic. It is also unclear whether topically applied Gramicidin penetrates the skin and reaches the sebaceous glands in significant concentrations.

Topical Gramicidin ointments are more likely to be effective at preventing secondary infections after acne lesions have been “popped” or drained, and these antibiotics may accelerate healing time and help prevent some scarring.