Sixty patients participated in a bacteriologically controlled, randomized, parallel group comparison of 2% mupirocin ointment (Bactroban) and oral erythromycin ethylsuccinate for the treatment of impetigo. The trial included clinical and bacteriologic evidence and safety assessments. The Investigator's Global Evaluation, which compared the overall efficacy and safety of the trial drugs, demonstrated a more favorable performance for the mupirocin regimen. This difference was statistically and clinically significant. There were no significant differences between the trial regimens for any of the other efficacy variables examined. The bacteriologic success rate was 100% for both treatment groups. There was a clinically significant difference in adverse experience rates between treatment groups, with four (13%) of the erythromycin-treated patients reporting six adverse experiences versus none of the mupirocin-treated patients. The results of the trial indicate that 2% mupirocin ointment is as safe and effective as oral erythromycin ethylsuccinate in the treatment of patients with impetigo.