A retrospective analysis was carried out of the results of 115 intensively-treated cancer inpatients receiving 91 treatment courses of amphotericin B given in an empirical fashion. Amphotericin B was administered over 1.5 to 2 hours at a dose of 0.6 to 0.7 mg/kg/day. Median duration of neutropenic fever before amphotericin B administration was 5 days (range 1 to 32 days) and median total amphotericin B dose was 480 mg (range 10 to 2450 mg). In 56 (61%) of 91 amphotericin B courses, neutropenic fevers resolved; this occurred a median of 3 days (range 1 to 15 days) after amphotericin B was begun and at a median dose of 120 mg (range 10 to 850 mg). Response to amphotericin was independent of positive cultures for fungus or sites of positive culture. Adverse reactions to amphotericin B included rigors (89% of courses), fever (23%), bronchospasm (9%), and transient hypotension (9%). Median increase above baseline serum creatinine in patients given amphotericin B was 0.5 mg/dl (range 0 to 2.6 mg/dl) compared to a median of 0.1 mg/dl (range 0 to 2.9 mg/dl) in a similar group of intensively-treated cancer patients who did not receive amphotericin B. Amphotericin B was well tolerated when given by rapid infusion and was associated with prompt resolution of neutropenic fever in the majority of patients.