At the present time there are three commercially available intravenous immunoglobulin (IVIG) preparations. There is no distinct therapeutic advantage for any one product over any other. Intravenous immunoglobulin is currently approved for the treatment of antibody deficiency syndromes and for acute and chronic idiopathic thrombocytopenic purpura. In addition, controlled clinical trials have demonstrated efficacy for the treatment of Kawasaki disease and for the prevention of the following infections: sepsis in preterm neonates, sepsis in infants with AIDS, and cytomegalovirus infection in the immune-compromised host. Open (uncontrolled) studies have suggested benefit in the treatment of neonatal sepsis, chronic Epstein-Barr virus infection, and a number of autoimmune diseases. Additional carefully designed studies must be completed before IVIG therapy can be recommended for these latter categories. In published reports, dosage of IVIG and intervals between infusions have varied considerably. For all current indications, the physician must therefore individualize treatment and thoroughly review any recent literature that may clarify guidelines to IVIG therapy. Significant adverse reactions are rare but high cost remains the main obstacle to more routine implementation.