WITH the introduction of methicillin sodium into clinical practice in 1960, the antibiotic vancomycin hydrochloride was relegated to the back shelves of the hospital pharmacy or deleted from the formulary. This appeared to be a natural evolutionary process: a toxic medicine replaced by one with less potential for serious untoward events. Vancomycin was known to be a difficult antibiotic for the patient to tolerate, since the administration of this compound could precipitate phlebitis, shaking chills, fever, and generalized skin eruptions. More importantly, however, vancomycin had produced irreparable harm to some patients, including deafness and renal failure.1We report why vancomycin should not be considered merely a drug of historic interest and why it remains an essential component of the physician's therapeutic arsenal. Three factors appear to contribute to the need for a second look at vancomycin: improvements in the manufacturing process have produced a preparation that has resulted in a