Since recommendations for the treatment of chancroid were made in 1985, in vitro and in vivo data indicate that the two drugs recommended, erythromycin (500 mg four times a day for 7 days) and ceftriaxone (250 mg intramuscularly in a single dose), remain effective. The alternative therapies of trimethoprim-sulfamethoxazole (160/800 mg twice a day for 7 days) and amoxicillin-clavulanic acid (500/125 mg three times a day for 7 days) also appear to be effective, although there has been little experience with these drugs in the United States. Single-dose trimethoprim-sulfamethoxazole (640/3,200 mg) now lacks the efficacy of other regimens. The experience with ciprofloxacin (500 mg twice a day for 3 days) has been favorable, and other quinolones may prove useful. Concurrent infection with human immunodeficiency virus appears to result in an increased rate of failure of treatment for chancroid, and such cases may require more prolonged therapy.