Poisoning means toxins or indigestion and, logos refers to basic science that explains the side effects of risk at the physical level. Toxicology is therefore a multidisciplinary field of study in the fields of Biology, Chemistry and Medicine, with a special focus on Pharmacology. This article discusses the presence of physical, biological and chemical agents in the Biological system and how they affect their functions. Toxicology specializes in the amount of toxic substances, method of exposure, species, age, sex and environment.