Betamethasone + Gentamicin + Miconazole is a combination of three medicines: Betamethasone , Gentamicin and Miconazole, which treats skin infections. Betamethasone is a steroid which blocks the production of certain chemical messengers (prostaglandins) that make the skin red, swollen and itchy. Gentamicin is an antibiotic which stops the growth of bacteria while Miconazole is an antifungal which stops the growth of fungi on the skin. Together, they treat your skin infection effectively.