Any toxin produced by a living organism
A toxic or poisonous substance produced by the biological processes of biological organisms.
A poisonous product formed by an organism, such as a pathogenic bacterium, a plant or an animal, usually having a high molecular weight, often a protein or a polysaccharide, but occasionally a low-molecular weight agent such as tetrodotoxin.
a poisonous substance produced during the metabolism and growth of certain microorganisms and some higher plant and animal species
a poison of plant or animal origin, especially one produced by or derived from microorganisms and acting as an antigen in the body.
A toxin is a harmful substance produced within living cells or organisms; synthetic toxicants created by artificial processes are thus excluded. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived from the word toxic.Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors.