toxin

noun

tox·​in ˈtäk-sən 

: a poisonous substance that is a specific product of the metabolic activities of a living organism and is usually very unstable, notably toxic when introduced into the tissues, and typically capable of inducing antibody formation

Did you know?

Toxins Are Often Found in Nature

Long before chemists started creating poisons from scratch, humans were employing natural toxins for killing weeds and insects. For centuries South American tribes have used the toxin curare, extracted from a native vine, to tip their arrows. The garden flower called wolfsbane or monkshood is the source of aconite, an extremely potent toxin. The common flower known as jimsonweed contains the deadly poison scopolamine. And the castor-oil plant yields the almost unbelievably poisonous toxin called ricin. Today we hear health advisers of all kinds talk about ridding the body of toxins; but they're usually pretty vague about which ones they mean, and most of these "toxins" wouldn't be called that by biologists.

Synonyms of toxin

• poison
• toxic
• disease
• venom

Examples of toxin in a Sentence

the toxin in scorpion venom

read a pamphlet on the toxin responsible for botulism, a food poisoning that can cause paralysis and even death in some cases

Recent Examples on the Web

Foad adds that the idea of eliminating toxins comes from sweat washing away trace amounts of heavy metals from the skin, rather than flushing toxins from inside the body. — Alexandra Frost, USA Today, 1 July 2026

That myth matters because social media often frames the practice as a way to flush toxins out through the skin. — Allison Palmer, Miami Herald, 30 June 2026

Their use may last seconds, but the plastic and its toxins live well beyond us. — Chicago Tribune, 28 June 2026

Patients might be women in their 30s with an autoimmune disease like lupus or people of any age exposed to such toxins as methamphetamines or, in the past, the fen-phen appetite suppressant drug of the 1990s, later withdrawn after being linked to heart disease. — Elizabeth Cooney, STAT, 26 June 2026

Word History

Etymology

International Scientific Vocabulary

First Known Use

1887, in the meaning defined above

Phrases Containing toxin

• botulinum toxin
• environmental toxin

Rhymes for toxin

• coxon
• oxen
• tocsin
• aflatoxin
• antitoxin
• digitoxin
• endotoxin
• exotoxin
• ferredoxin
• mycotoxin
• neurotoxin
• picrotoxin

Kids Definition

toxin

noun

tox·​in ˈtäk-sən 

: a substance produced by a living organism (as a bacterium) that is very poisonous to other organisms and that usually causes antibody formation compare antitoxin

Etymology

derived from Latin tox- "poisonous" and English -in "chemical compound"; tox- from toxicum "poison," from Greek toxikon "arrow poison," from toxon "bow, arrow" — related to intoxicate, toxic see Word History at intoxicate

Medical Definition

toxin

noun

tox·​in ˈtäk-sən 

: a colloidal proteinaceous poisonous substance that is a specific product of the metabolic activities of a living organism and is usually very unstable, notably toxic when introduced into the tissues, and typically capable of inducing antibody formation