Autoimmune thrombocytopenic purpura (AITP) is a common nonmalignant disease that can be complicated by life-threatening haemorrhage. The thrombocytopenia is due to antiplatelet antibodies that opsonise the platelet membrane, leading to platelet destruction by phagocytes, principally in the spleen. Acute and chronic forms are observed; spontaneous remission only occurs in the former. Treatment with high doses (2 g/kg) of intravenous immunoglobulin (IVIg) originating from the plasma of blood donors is frequently given at disease onset in severe thrombocytopenia, as it regularly induces rapid platelet recovery. The best responses are obtained when IVIg is administered over 2 days and when ;intact' (chemically unmodified) immunoglobulin concentrates are used. However, the effect is usually transient, severe adverse effects may occur and the cost is high, leading many physicians to reduce the dosage of IVIg and to limit its use to patients with life-threatening complications and contraindications to corticosteroids. Finally, even if repeated administration of IVIg can sometimes induce prolonged remissions, there is no proof that the treatment can cure a significant number of patients with chronic AITP. Anti-D (Rhesus) human immunoglobulin concentrates can also transiently increase the platelet count in patients with AITP. However, the platelet response is slower than with IVIg and use should be limited to selected patients in whom a transient, possibly delayed, increase in the platelet count is required, or where splenectomy is contraindicated.