A growing body of literature documents that intravenous immunoglobulin prophylaxis and therapy is becoming applied to a steadily growing list of new indications. Some of these new indications have led to the use of intravenous immunoglobulin therapy in doctors offices, far from the hospital environment. Being stable products purified from blood or plasma donations, intravenous immunoglobulins must be considered as biological products in addition to their status as pharmaceutical products. This makes the study of adverse reactions reach beyond a mere drug safety surveillance programme into the realms of good manufacturing procedures guaranteeing not only intravenous tolerance but also sterility with regard to transfusion transmitted agents. The initially perceived adverse effects, stemming from complement activating aggregated immunoglobulin G, had the effect of slowing down widespread introduction of intravenous immunoglobulin therapy in the late 1970s. These adverse effects have now been eliminated with amendment of the appropriate manufacturing steps. However, new adverse effects, such as hyperviscosity, aseptic meningitis or renal insufficiency, have been observed which can be assigned to certain comnpounds of intravenous immunoglobulin, to administration regimens or to special patient characteristics. Adverse effects can be divided into 3 types: immediate adverse effects (those that occur during the infusion, e.g. anaphylactoid reactions); delayed adverse effects (those that occur hours to days after initiation of the infusion, e.g. renal, pulmonary, dermatological adverse effects, hyperviscosity, aseptic meningitis, arthritis, cerebral infarction, haemolysis and leucopenia) and; late adverse effects (e.g. transmission of infectious agents). We conclude from our analysis, that in general, intravenous immunoglobulin may be considered a well tolerated medical agent provided the indication for use is chosen carefully and use is monitored by a physician familiar with contraindications, risks, adverse effects and their appropriate management.