The use of high-dose corticosteroids for graft-versus-host disease (GVHD) treatment represents a major risk factor for long-term invasive fungal infections. The aim of this study was to investigate the safety and tolerance of weekly prophylactic administration of once-weekly high-dose (7.5 mg/kg) of liposomal amphotericin B (L-AmB) therapy in 21 adult patients receiving high-dose prednisone (2 mg/kg/day) for acute GVHD therapy after reduced intensity conditioning (RIC) allogeneic stem cell transplantation (allo-SCT). Patients received a median of 4 (range, 1-8) infusions of L-AmB. Seven patients (33%; 95% confidence intervals (CI), 13-53%) discontinued taking the study drug owing to study drug-related adverse events, including elevated serum creatinine (>1.5 times from baseline values; n=5), hypotension and pain (n=1), and violent chest pain and arrhythmia (n=1). The overall frequency of infusion-related reactions was 29% (n=6; 95% CI, 10-48%), but these reactions were always transient and relieved by stopping the infusion. This safety data provide support for an efficacy study of this prophylaxis strategy, because this may help further improving the outcome of RIC or nonmyeloablative allo-SCT.