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

Washing blueberries removes dirt and toxins that may cling to the fruit during handling and transporting from farm to store. — Martha Stewart, 3 July 2026

It is caused by eating or drinking food contaminated with either bacteria, viruses, parasites or a harmful toxin. — Sheah Rarback, Miami Herald, 2 July 2026

Additionally, some varieties contain toxins that deer cannot tolerate. — Steve Bender, Southern Living, 7 July 2026

Ferrer-Clement says this is important for cancer patients, whose livers may already be compromised while processing toxins released during treatment. — Shelby Hartman, Los Angeles Times, 8 July 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