The use of high-dose chemotherapy and the subsequent prolonged neutropenia in patients with haematological diseases has resulted in an increased incidence of fungal infections. The diagnosis and treatment of these infections in neutropenic patients pose major therapeutic problems. The only drug with proven efficacy in the treatment of deep-seated fungal infections, including invasive aspergillosis, is amphotericin B. Unfortunately, this drug has adverse side effects, most importantly dose-dependent nephrotoxicity; furthermore, some patients fail to show a response to amphotericin B. We have treated 20 patients undergoing myeloablative chemotherapy and/or bone marrow transplantation for haematological diseases with liposomal amphotericin (AmBisome) for proven or suspected aspergillosis. Eighteen patients had diffuse interstitial pneumonitis and two patients had suspected fungal liver abscesses. Five patients had mycologically proven fungal infection and of these, three patients (60%) showed a complete response to liposomal amphotericin. Eleven patients received liposomal amphotericin because of the failure of conventional amphotericin B to eradicate proven or suspected fungal infection. Five of these 11 patients (45%) showed a complete clinical response to liposomal amphotericin. Eight patients received liposomal amphotericin because of pre-existing renal impairment or nephrotoxicity caused by conventional amphotericin B. Four of these patients (50%) showed a response to liposomal amphotericin. Recovery from probable fungal infection in this group of patients occurred when there was complete remission of underlying disease and recovery of neutrophil counts, when they were concurrently treated with liposomal amphotericin.