AskDefine | Define toxin

Dictionary Definition

toxin n : a poisonous substance produced during the metabolism and growth of certain microorganisms and some higher plant and animal species

User Contributed Dictionary



The word "toxin" comes from the Greek "toxikon" which means "arrow poison".



  1. A toxic or poisonous substance.

Related terms


a toxic or poisonous substance
  • Hungarian: méreg

Extensive Definition

A toxin (Greek: , toxikon, lit. (poison) for use on arrows) is a poisonous substance produced by living cells or organisms that is active at very low concentrations. Toxins can be small molecules, peptides, or proteins and are capable of causing disease on contact or absorption with body tissues by interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their severity, ranging from usually minor and acute (as in a bee sting) to almost immediately deadly (as in botulinum toxin).
Biotoxins vary greatly in purpose and mechanism, and can be highly complex (the venom of the cone snail contains dozens of small proteins, each targeting a specific nerve channel or receptor), or relatively small protein.


Biotoxins in nature have two primary functions:
Some of the more well known types of biotoxins include:
Ricinis is a plant toxin found in the castor bean plant.

Environmental toxins

Non-technical usage

When used non-technically, the term "toxin" is often applied to any toxic substances. Toxic substances not of biological origin are more properly termed poisons. Many non-technical and lifestyle journalists also follow this usage to refer to toxic substances in general, though some specialist journalists at publishers such as the BBC and The Guardian maintain the distinction that toxins are only those produced by living organisms.
In the context of alternative medicine the term is often used non-specifically to refer to any substance claimed to cause ill health, ranging anywhere from trace amounts of pesticides to common food items like refined sugar or additives like artificial sweeteners and MSG.

See also

toxin in Catalan: Toxina
toxin in German: Toxin
toxin in Esperanto: Toksino
toxin in Spanish: Toxina
toxin in French: Toxine
toxin in Hebrew: רעלן
toxin in Italian: Tossina
toxin in Japanese: 毒
toxin in Dutch: Toxine
toxin in Romanian: Toxină
toxin in Russian: Токсин
toxin in Swedish: Toxin
toxin in Chinese: 毒素

Synonyms, Antonyms and Related Words

abomination, acaricide, anthelmintic, antibiotic, antiseptic, atrocity, bad, bane, befoulment, blight, bug bomb, carbamate insecticide, chemosterilant, chlorinated hydrocarbon insecticide, contact poison, corruption, crying evil, damage, defilement, defoliant, despoliation, destruction, detriment, disinfectant, eradicant, evil, fumigant, fungicide, germicide, grievance, harm, havoc, herbicide, hurt, ill, infection, injury, insect powder, insecticide, microbicide, mischief, miticide, organic chlorine, organic phosphate insecticide, outrage, pesticide, poison, pollution, rat poison, roach paste, roach powder, rodenticide, stomach poison, systemic, systemic insecticide, the worst, toxic, toxicant, venin, venom, vermicide, vexation, virus, weed killer, woe, wrong
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