Although US immune globulin intravenous (human) (IGIV) products have been regarded as safe, it is important to recognize that many of the controlled clinical studies of IGIVs have been of modest size and have limited power to define the incidence of only the most common adverse events (AEs). A significant number of "postmarketing" serious AEs affecting renal, cardiovascular, CNS, integumentary, and hematologic organ systems have been reported. Variables potentially affecting the risk and intensity of adverse events associated with administration of IGIV include patient age, underlying condition, history of migraine, cardiovascular or renal disease, dose, concentration, rate of infusion, specific brand/formulation/excipients, and lot(s) of the particular IGIV product being administered. Each manufacturer's IGIV preparation is a unique product carrying its own specific evidence-based indications and safety profile. In view of the seriousness of potential adverse effects of IGIV products, and current lack of data surrounding their frequency, clinicians are advised to limit their prescription of these products for conditions for which efficacy is supported by adequate and well-controlled clinical trials. Prescribers should pay close attention to patient selection; consider the potential risk/benefit ratio vis-a-vis alternate therapies; and familiarize themselves with the identification, management, and proposed strategies to minimize the risks of IGIV.