Since 1946 the development of fractionation and purification methods of human plasma led to biologic immunoglobulin for intravenous use (IVIG). In 1980 a child with refractory immune thrombocytopenia (ITP), bleeding and secondary hypogammaglobulinaemia due to long term immunosuppressive treatment got IVIG. His platelet counts dramatically increased. In 13 consecutive children with ITP, but without hypogammaglobulinaemia, similar rapid platelet increases were observed and confirmed in a controlled, multicentre study. During the past three decades this biologic treatment modality evoked clinical and laboratory research on the mechanisms of action and in disorders with similar immune pathogenesis. It was recognised that IVIG modulates the disturbed immune response in multiple, synergistic ways between the different components of the immune system. Beside other immune hematologic disorders other inflammatory and autoimmune diseases, mainly in the field of neurology and dermatology, IVIG showed beneficial effects. The worldwide consumption of IVIG increased from 300 kg per year in 1980 to 100 tonnes per year in 2010. Due to the heterogeneity of immunopathological mechanisms of autoimmune diseases evidence based indications of IVIG remain rare and off label use high. Registries of large numbers of patients and first endpoints of defining less heterogenous subgroups in immune related disorders are the next steps toward establishment of evidence based IVIG indications.