Toxicology the science of poisons (or) toxins concerned with the chemical nature of poisonous substances and their adverse effects in biological systems is a complex, interdisciplinary subject, straddling the fields of chemistry, biology, pharmacology, medicine, genetics, economics, and law. Various subdisciplines within toxicology include, Aquatic toxicology, Chemical toxicology, Ecotoxicology, Environmental toxicology, Forensic toxicology, and Medical toxicology, Toxicogenomics, Toxicon, Occupational toxicology, Regulatory toxicology.
Toxicology is highly eclectic science and human activity contributing to a broad spectrum of other sciences and human activities. Molecular biology, in the last two decades has contributed to dramatic advances in toxicology. Toxicology significantly contributes in the aspects of medicine as forensic medicine, pharmacy and pharmacology, public health, and industrial hygiene and in a most important way to veterinary medicine agriculture as the development and safe use of agricultural chemicals. The contribution of toxicology to environmental studies has become increasingly important in recent years. Toxicology research spans an array of topics ranging from the molecular to population level consequences of toxicant exposure. NTP (National Toxicological Programme) has a broad mandate to provide toxicological characterizations for chemicals and agents of public health concern and strives to balance the selection of chemicals for study. This has resulted in a diverse research program, with emphasis on synthetic industrial chemicals, pesticides, various pharmaceuticals, and food additives. In general, these initiatives are broad-based and include various health-related end points. The goal of toxicity assessment is to identify adverse effects of a substance which depend on two main factors: i) routes of exposure (oral, inhalation, or dermal) and ii) dose (duration and concentration of exposure). To explore dose, substances are tested in both acute and chronic models. Generally, different sets of experiments are conducted to determine whether a substance causes cancer and to examine other forms of toxicity.
Clearly, toxicology is preeminently an applied science which has been dedicated to the enhancement of the quality of life and the protection of the environment. In recent decades the field of toxicology has expanded enormously, and has brought a change from a primarily descriptive science to one which utilizes an extensive range of methodology to study the mechanisms involved in toxic events.