Vancomycin is an antibiotic. Oral (taken by mouth) vancomycin fights bacteria in the intestines. Vancomycin is used to treat an infection of the intestines caused by Clostridium difficile, which can cause watery or bloody diarrhea. Vancomycin is also used to treat staph infections that can cause inflammation of the colon and small intestines. Oral vancomycin works only in the intestines. This medicine is not normally absorbed into the body and will not treat other types of infection. An injection form of this medication is available to treat serious infections in other parts of the body. Vancomycin may also be used for purposes not listed in this medication guide.