Viral and bacterial infections are a serious cause of morbidity and mortality in patients immunocompromised as a result of malignancy, burns, trauma, viral infections or chemotherapy. The development of safe and effective antibody preparations suitable for intravenous use have transformed the lives of patients suffering from forms of primary immunodeficiency characterised by antibody deficiency. However, the role of intravenous immunoglobulin (IV IgG) preparations in the treatment of secondary immunodeficiencies is less clear and although many anecdotal reports exist for the use of IV IgG in various secondary immunodeficiencies (Table 1), there have been few controlled trials of a sufficient size that have demonstrated clear-cut efficacy in many of the suggested new indications.