The safety of AmBisome was evaluated in 187 transplant recipients treated for 197 episodes. Patients included 89 bone marrow transplant recipients, 64 liver transplant recipients, 20 renal transplant recipients and 14 recipients of combined organs. AmBisome was instituted for verified invasive fungal infection in 34 cases, suspected invasive fungal infections in 80 cases and as prophylaxis in 83 cases. AmBisome was given for a median of 11 days (range 1-112 days) with a maximum daily dose of 1.49 +/- 0.70 mg/kg/day (mean +/- SD). The total cumulative dose of AmBisome was 1.11 +/- 1.78 g (mean +/- SD). Side-effects definitely attributed to AmBisome therapy included low potassium (n = 3), low back pain (n = 3), dyspnoea (n = 2), allergic rash (n = 1), nausea and vomiting (n = 1), confusion (n = 1), rise in alkaline phosphatase (n = 1) and cholecystitis (n = 1) with an overall incidence of 13 of 197 (7%). AmBisome was discontinued due to side-effects in 6 (3%) of the cases. During AmBisome treatment the mean cyclosporin dose was 9.6 +/- 28.8 mg/kg/day. Compared to pre- and post-AmBisome therapy there was a significantly increased cyclosporin concentration in blood during AmBisome therapy. Side-effects with possible association to AmBisome therapy included low serum potassium (36%), increase in serum creatinine (31%), rise in alkaline phosphatases (26%) and fever (3%). The overall mean increase in serum creatinine was 20%. Other possible side-effects like headache, abdominal pain, rash, rise in bilirubin, cramps and pancreatitis was seen in single patients.(ABSTRACT TRUNCATED AT 250 WORDS)