Introduction and Review

Immunostimulants, which are also known as immunostimulators are substances comprising of drugs and nutrients that stimulate the immune system by inducing activation, or increasing activity of any of its components. During the last two decades very intensive investigations are carried out for the production of a novel category of biologically active substances known to the world as “Immunostimulants”. They are the products derived from natural or synthetic origin with different chemical characteristics and varied modes and mechanism of action (Petrunov et al., 2007). Immunostimulants activate different elements and mechanisms of the immune system of humans and animals, to re-inforce the body’s natural resistance in order to successfully and amiably cope with various viral and bacterial infections or to help in the treatment of disastrous and chronic ailments and severe immune-suppression. The immunostimulants promote phagocytosis, activates properdin and complement systems, and helps in the release of interferons like  and . Immunostimulants promote synthesis of specific antibodies and cytokines and represent an emerging class of drugs for the treatment of infectious disorders. The two main categories of immunostimulants include: