ABSTRACT
Toxicology is both a science and an art because as a science it involves observation and data-gathering, while as an art, it uses data to predict the outcomes of exposure on human and animal populations. Broadly, toxicology is the study of poisons, or the identification and assessment of undesirable impacts linked with the exposure to physical, chemical, or biological agents. It studies the characteristic features of toxic substances, their mechanism of action and provides input both for analysing the aetiology, the possibility of a link between dose and impact, the incidence of occupational diseases and associated health conditions. The science of toxicology is as old as the history of human civilization, from the time when early humans started distinguishing between consumable and non-consumable eatables. Toxicology has numerous sub-disciplines or sub-specialties. Ecotoxicology as a branch of toxicology deals with the effects of toxic chemicals on biological systems, mainly the population, community, ecosystem and biosphere. This chapter, besides describing the basic terminology, gives the historical background and important landmarks in the history of toxicology, sub-disciplines of toxicology, ecotoxicology as a sub-discipline of toxicology, the relationship of toxicology with other disciplines and its scope.
