A chemical substance that affects the processes of the mind or body; a substance used in the diagnosis, treatment, or prevention of a disease

An addictive drug such as opium that releases pain, alters mood and behavior, and causes sleep or feelings of mental numbness.

A naturally occuring or manufactured substance that can cause severe harm or death if ingested, inhaled, or absorbed through the skin.

The degree to which a substance is poisonous or can cause injury.

A poisonous substance naturally produced by certain plants, animals, and bacteria that is capable of causing disease or death in humans; a subgroup of poisons

Stimulants increase feelings of energy and alertness while suppressing appetite.

Drugs, such as barbiturates and benzodiazepines, that relive anxiety and produce sleep.

Forensic toxicology seeks to identify poisons or drugs in criminals and victims and their likely effects on those people.

Heavy metals and pesticides are also common poisons found in humans.

Accidental deaths from drug overdoses are more common than deaths from poisoning.