Intravenous immunoglobulins (IVIG) are currently used to treat several diseases including toxic shock syndrome, different vasculitis, toxic epidermolysis syndrome, Kawasaki syndrome, myasthenia gravis, etc. Primarily, IVIG are used with the aim of tampering with the immune system, taking advantage of their pleiotropic effects. The rationale behind the use of IVIGs includes their interaction with soluble molecules and surface membrane receptors ultimately influencing the global immune response and its inflammatory and anti-inflammatory paths. Moreover, IVIGs play a complex role, binding exogenous molecules, influencing the path of presentation of antigens, and interacting with mediators of the specific immune response, mostly depending on lymphocytes.