Toxicology is the basic science of poisons. As such it focuses on understanding the adverse effects of chemicals on living organisms by applying knowledge and techniques from biochemistry, chemistry, physiology, molecular biology, genomics and proteomics, and other disciplines.
Toxicologists are concerned with the hazards associated with chemicals encountered through occupational and environmental exposures including their occurrence as air and water pollutants. They are also concerned with risks resulting from the use of chemicals as pharmaceutical agents and food additives. In modern toxicology, emphasis is placed on understanding the mechanisms involved in the actions of toxicants in order to determine their relevance to human health. To accomplish these goals, studies are conducted using animal models at all levels ranging from whole animals to subcellular fractions as well as a large number of cell culture systems.