Forty patients with papulo-pustular rosacea were treated for 12 weeks on a random double-blind basis either with oxytetracycline 250 mg twice daily or with metronidazole 200 mg twice daily. Both drugs produced an improvement which was greater after 12 weeks than after 6 weeks, but there was no significant difference between them. Metronidazole appears to be a safe and effective drug for the treatment of rosacea.