Intravenous immunoglobulin (IVIG) has become a mainstay of treatment for acute and chronic immune thrombocytopenic purpura (ITP). The efficacy and safety of Privigen, a new, ready-to-use, 10% liquid human IgG formulation, was evaluated in this open-label, multicentre study. Privigen infusions (1 g/kg per day for 2 consecutive days, days 1 and 2) were given to 57 adolescent and adult patients with chronic ITP and platelet counts < or =20 x 10(9)/l. By day 7, 80.7% of patients (95% CI, 69.2, 89.3) achieved platelet counts of > or =50 x 10(9)/l. Correspondingly, haemorrhage number and severity were significantly reduced. Adverse events were generally mild or moderate and typical of underlying disease and IVIG treatment. Privigen was well tolerated - 104 of 114 infusions were performed at the maximum permitted infusion rate (4 mg/kg/min). Thus, in patients with chronic ITP, a two-day regimen of Privigen was effective in increasing platelet count, reducing bleeding events and was well tolerated.