Toxicology may even be a discipline, overlapping with biology, chemistry, pharmacology, and drugs, that involves the study of the adverse effects of chemical substances on living organisms and then the practice of diagnosing and treating exposures to toxins and toxicants. The affiliation between dose and its effects on the exposed organism is of high significance in pharmacology. Factors that influence chemical toxicity include the amount route of exposure, species, age, sex, and setting. Toxicologists are specialists on poisons and poisoning.