Two hundred and three patients with skin and skin structure infections were treated with isepamicin once daily or amikacin twice daily in an open, randomised, comparative multicentre trial. Patients were randomised to treatment with isepamicin or amikacin in a 2:1 ratio. Severe infections (63 patients) were treated with isepamicin 15 mg/kg once daily (n = 15) or amikacin 7.5 mg/kg twice daily (n - 18), less severe infections (140 patients) with isepamicin 8 mg/kg once daily (n = 93) or amikacin 7.5 mg/kg twice daily (n = 47). The overall clinical response rate at the end of treatment was excellent in all treatment groups (94-96% cured or improved) with no significant differences between isepamicin and amikacin in patients with either server or less severe infections. The most commonly isolated target pathogens were Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis and Staphylococcus aureus. Overall, in patients who had a valid target pathogen isolated prior to treatment and who met other evaluability criteria, bacteriological eradication was achieved in over 90% of patients; amikacin patients with severe infections had a somewhat lower eradication rate (82%). Over all infections, 4/110 (4%) patients in the isepamicin group and 5/54 (9%) patients in the amikacin had organisms which persisted. Adverse events were reported in 12% of patients in the isepamicin group and 6% in the amikacin group. The most frequently reported adverse event in the isepamicin group as headache. Two patients (one in each treatment group), both of whom experienced skin rashes, were withdrawn. Potentially clinically significant changes in serum creatinine occurred in two patients, who received isepamicin and one who received amikacin (who was withdrawn from the study). Ototoxicity was rare, occurring in one patient treated with isepamicin.