Toxin

A toxin is a harmful substance produced within living cells or organisms. Toxins can be small molecules, peptides, or proteins that can cause disease in body tissues.

Toxins vary greatly in their toxicity, ranging from minor (such as a bee sting in normal people) to almost immediately deadly (such as botulinum toxin). Toxins are secondary metabolites, organic compounds not directly involved in an organism's growth, used in defence.

Toxins in nature have two primary functions:

• Predation, such as in the spider, snake, scorpion, jellyfish, and wasp
• Defence as in the bee, ant, termite, wasp, and poison dart frog

Terminology

Toxins are distinguished from other chemical agents by their method of production — the word toxin does not specify method of delivery (compare with venom and the broader meaning of poison— these can also cause harm to organisms). It simply means it is a biologically produced poison.

According to an International Committee of the Red Cross review of the Biological Weapons Convention, "Toxins are poisonous products of organisms; unlike biological agents, they are inanimate and not capable of reproducing themselves", and "Since the signing of the Constitution, there have been no disputes among the parties regarding the definition of biological agents or toxins".

On a broader scale, toxins may be classified as either

• exotoxins, excreted by an organism, or
• endotoxins, released when bacteria are broken open or digested.

Toxins can be further classified by their origin, as fungal toxins, microbial toxins, plant toxins, or animal toxins.

Types of toxins

• Cyanotoxins, produced by cyanobacteria
• Dinotoxins, produced by dinoflagellates
• Cytotoxins cause necrosis (i.e., death) in the cells they encounter. Organisms producing cytotoxins include:
  • Apitoxin, from honey bees
  • Brown recluse or violin spider
  • Hemotoxin, from vipers
  • Puff adder

• • Ricin, from castor beans
  • Necrotizing fasciitis (caused by the "flesh eating" bacterium Streptococcus pyogenes) – produces a pore forming toxin
• Hemotoxin, causes destruction of red blood cells (hemolysis) - this is a specific form of a cytotoxin.
• Neurotoxins primarily affect the nervous systems of animals. The group neurotoxins generally consists of ion channel toxins that disrupt ion channel conductance. Organisms producing neurotoxins include:
  • Black widow spider.

• • Most scorpions
  • Box jellyfish
  • Elapid snakes
  • Cone snail
  • Blue-ringed octopus
  • Venomous fish
  • Frogs
  • Palythoa coral
  • Various algae, cyanobacteria and dinoflagellates
• Myotoxins are small, basic peptides found in snake and lizard venoms that cause muscle tissue damage. Organisms with myotoxins include:

rattlesnakes

• • Mexican beaded lizard
• Phototoxin, causes dangerous photosensitivity

Environmental toxins

The term "environmental toxin" can sometimes explicitly include synthetic contaminants such as industrial pollutants and other artificially made toxic substances. As this contradicts most formal definitions of the term "toxin", it is important to confirm what the researcher means when encountering the term outside of microbiological contexts.

Environmental toxins from food chains that may be dangerous to human health include:

• Paralytic shellfish poisoning (PSP)
• Amnesic shellfish poisoning (ASP)
• Diarrheal shellfish poisoning (DSP)
• Neurotoxic shellfish poisoning (NSP)

Misuse of the term

In the context of alternative medicine, the term "toxin" is used to refer to a substance alleged to cause ill health. This could range from potentially dangerous pesticides, to substances produced in the body by intestinal fermentation (auto-intoxication), to food ingredients such as table sugar, monosodium glutamate (MSG), and aspartame.

The use of detoxification or detox as justification for treatments, such as infrared saunas, or diets, a marketing technique to frighten the public into seeking treatments that claim to remove unspecified toxins. These claims can be harmful financially and physically. According to the article Detox Scams are Worthless and Potentially Dangerous, healthy kidneys and liver are all that most people need to remove anything potentially toxic.