The science of poison that studies toxic substances with respect to their: source, properties, mechanism of action, toxic effect, detection, clinical manifestations and management etc. Toxicity can affect the animals, plants, bacteria and humans beings. Toxicity is basically three types-acute toxicity, sub chronic toxicity and chronic toxicity In U.S. there were 667 poison exposure reported per 100,000 populations. The highest incidence of poison exposure occurred in below 5 years of age group (8,327 and 8,085 exposures/100,000 children in the respective age groups) . In US 2015, According to U.S. Poison center approximately 78.4% of poison exposures were unintentional (general, environmental, bite, food poisoning, occupational and unknown), 17.6% were intentional(Abuse, misuse, Suspected suicide, unknown), ,and 2.4% were adverse drug reactions99% of poison exposures are unintentional below the age group of 6 years.