The branch of science that skudies the effects of chemicals on living systems; especially, the effects of toxins (poisons) on health and the environment.

The use of toxicology to aid a medicolegal investigation of death and poisoning.

Many toxic substances do not produce characteristic lesions, so if a toxic reaction is suspected, visual investigation may not provide an adequate deduction.

A forensic toxicologist must consider the context of an investigation, in particular any physical symptoms recorded, and any evidence collected at a crime scene that may narrow the search; such as, pill bottles, powders, trace residue, and any available chemicals.

Provided with this information and samples with which to work, the forensic toxicologist must determine which toxic substances are present, in what concentrations, and the probable effect of those chemicals on the human subject being investigated.