The study of immune dysfunction is called Immunotoxicology. It is because of exposure of an organism to foreign chemical substance identified within a creature that's not usually produced by or estimated to be existent within that organism. Immune dysfunction may effect in the decline of the action of the immune system. Immunotoxic substances, such as chemicals, pesticides, or drugs, can have adversarial efsfects on the working of the immune system. The well-known effects comprise enlarged susceptibility to infections or tumors as a results of humoral and/or cellular immunity being co-operated (immunosuppression), autoimmune diseases, chronic inflammation, and progress of allergies.