Abrins
Abrin is a potent toxin that has been isolated from the seeds of Abrus precatorius (or Rosary pea). The mechanism of toxic action of abrin is identical to that of ricin, but the toxicity of abrin in mice is 75 times that of ricin (0.04 µg/kg for abrin compared to3 µg/kg for ricin.) The diagnosis, clinical features, treatment, protection, prophylaxis and so on is also the same for both abrin and ricin intoxications. Abrin may be considered to be an available toxin for weaponizing because its source, Abrus precatorius, may be easily cultivated and the preparation of the pure toxin is not complicated. For nations or terrorists who lack the money to spend on nuclear weapons and other high-tech killing instruments, toxin warfare offers horrific appeal: biological/toxin weapons are cheap, easy to make and simple to conceal. Even small amounts, if effectively used, could cause massive injuries and make many suffer.

Anatoxins
The anatoxins are a group of low molecular weight neurotoxic alkaloids first described in the fresh-water cyanobacteria Anabaena flos-aquae from Canada. Anatoxins are produced by various species of cyanobacteria, in isolation or in combination with hepatotoxins. Not all strains of the causative species are toxic and there are no taxonomical or behavioural clues to the presence or absence of anatoxin in a particular sample. Three common anatoxins have been described: anatoxin-a and homoanatoxin-a are secondary amines and anatoxin-a(S). The basic mechanism of muscle contraction consists of the neurotransmitter acetylcholine propagating from the axon of a nerve cell to the ion channels in the wall of a muscle cell. The acetylcholine binds to the ion channel, opening it and allowing the migration of ions across the muscle cell wall, thus propagating the electrical signal for the cell to contract. It is then the job of the enzyme cholinesterase to deactivate the cholinesterase and allow the ion channel to re-close, relaxing the contraction.

Botulinum Toxin
Botulinum toxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport and misuse; and the need for prolonged intensive care among affected persons. An outbreak of botulism constitutes a medical emergency that requires prompt provision of botulinum antitoxin and, often, mechanical ventilation, and it constitutes a public health emergency that requires immediate intervention to prevent additional cases. Botulinum toxin is the most poisonous substance known. A single gram of crystalline toxin, evenly dispersed and inhaled, would kill more than 1 million people, although technical factors would make such dissemination difficult. The basis of the phenomenal potency of botulinum toxin is enzymatic; the toxin is a zinc proteinase that cleaves one or more of the fusion proteins by which neuronal vesicles release acetylcholine into the neuromuscular junction. France, the United Kingdom, Canada and the United States conducted bioweapons research in the use of botulinum toxin as a biological weapon. Iraq is known to have produced and weaponized botulinum toxin.

Bungarotoxins
Bungarotoxins are the neurotoxic proteins from the venom of the banded or formosan krait (bungarus multicinctus, an elapid snake).

Ciguatoxins
Ciguatoxin is a large, heat stable, polyether toxin produced by certain strains of Gambierdiscus toxicus found in tropical and subtropical waters around the world. Ciguatoxin is the toxin responsible for the poisoning syndrome known as ciguatera, which is characterized by numbness and tingling around the mouth, hands and feet; joint and muscle pains with weakness or cramps; vomiting, diarrhea, chills, itching, headache, sweating and dizziness; and reversal of temperature sensation, where cold things feel hot and hot things feel cold. These symptoms all appear to arise because of ciguatoxin's ability to activate the sodium channels found in nerves and muscles. Ciguatera may continue for a week or more in mild cases, and up to several months or more in some more severely affected victims. There is as yet no validated test available for the reliable detection of ciguateric fish.

Clostridium Perfringens Toxin
Clostridium perfringens is a common anaerobic bacterium associated with three distinct disease syndromes; gas gangrene or clostridial myonecrosis; enteritis necroticans (pig-bel); and clostridium food poisoning. Each of these syndromes has very specific requirements for delivering inocula of C. perfringens to specific sites to induce disease, and it is difficult to imagine a general scenario in which the spores or vegetative organisms could be used as a biological warfare agent. There are, however, at least 12 protein toxins elaborated, and one or more of these could be produced, concentrated and used as a weapon. Waterborne disease is conceivable, but unlikely. The alpha toxin would be lethal by aerosol. Other toxins from the organism might be co-weaponized to enhance effectiveness. For example, the epsilon toxin is neurotoxic in laboratory animals.

Ricins
Ricin was found by Stillmark in 1889 as the first plant lectin from the seeds of the castor plant, Ricinus communis. The toxicity of castor beans has been known since ancient times, and more than 750 cases of intoxication in humans have been described. Like other potential intoxications on the unconventional battlefield, epidemiological findings will likely play a central role in diagnosis. The observation of multiple cases of very severe pulmonary distress in a population of previously healthy young soldiers, linked with a history of their having been at the same place and time during climatic conditions suitable for biological warfare attack, would be suggestive of ricin intoxication.

Saxitoxins
Saxitoxin is the parent compound of a family of chemically related neurotoxins. In nature they are predominantly produced by marine dinoflagellates, although they have also been identified in association with such diverse organisms as blue-green algae, crabs and the blue-ringed octopus. Human intoxications are principally due to ingestion of bivalve mollusks, which have accumulated dinoflagellates during filter feeding. The resulting intoxication, known as paralytic shellfish poisoning (PSP), is known throughout the world as a severe, life-threatening illness requiring immediate medical intervention. The natural route of exposure to these toxins is oral. In a BW scenario, the most likely route of delivery is by inhalation or toxic projectile. In addition, saxitoxin could be used in a confined area to contaminate water supplies.

Shigatoxins
Shigellosis is an infectious disease caused by a group of bacteria called Shigella. Most who are infected with Shigella develop diarrhea, fever and stomach cramps starting a day or two after they are exposed to the bacterium.

Staphylococcal enterotoxins
Staphylococcal Enterotoxin B (SEB) is one of several exotoxins produced by Staphylococcus aureus, causing food poisoning when ingested. A BW attack with aerosol delivery of SEB to the respiratory tract produces a distinct syndrome causing significant morbidity and potential mortality.

Trichothocene Toxins
The trichothecene mycotoxins are a diverse group of more than 40 compounds produced by fungi. They are potent inhibitors of protein synthesis, impair DNA synthesis, alter cell membrane structure and function and inhibit mitochondrial respiration. Secondary metabolizes of fungi, such as T-2 toxin and others, produce toxic reactions called mycotoxicoses upon inhalation or consumption of contaminated food products by humans or animals. Naturally occurring trichothecenes have been identified in agricultural products and have been implicated in a disease of animals known as moldy corn toxicosis or poisoning. There are no well-documented cases of clinical exposure of humans to trichothecenes. However, strong circumstantial evidence has associated these toxins with alimentary toxic aleukia (ATA), the fatal epidemic seen in Russia during World War II, and with alleged BW incidents ("yellow rain") in Cambodia, Laos and Afghanistan.