What does a Toxicologist Do? What is Toxicology? Toxicology is defined as the scientific study of harmful effects also known as toxins and toxicants on living organisms including human beings, animals, the environment and ecosystems. This area of study focuses on understanding the nature, intensity and mechanism levels of drug substances. Moreover it assesses the risks that are associated with harmful substances. In the health sector, clinical toxicology focuses on detecting and treating ove...