Immunomodulatory therapy promotes modulation in immune system of host which has three types of immunomodulatory therapy strategies. It involve the usage of immunosuppressant drugs to reduce the impact of the immune system natural action or the use of immunostimulant drugs to increase immune system response and the use of tolerogens which condition the immune system based on requirement in order to tolerate tissue changes such as transplanted organs. Each category of treatments is designated for specific immune system problems. Immunosuppressant drugs and tolerogens are used for the purpose of controlling immune system response such as treating autoimmune diseases like multiple sclerosis (MS) and organ transplants. Immunostimulant drugs are utilized to enhance the immune system response in cases where immune system is weakened, such as with cancer, AIDS, and other life-threatening infections or diseases.