Poison toxicity

In biology, poisons are substances that can cause death, injury or harm to organs, usually by chemical reactions or other activity on the molecular scales, when an organism is exposed to a sufficient quantity.The fields of medicine (particularly veterinary) and zoology often distinguish a poison from a toxin, and from a venom. Toxins are poisons produced by organisms in nature, and venoms are toxins injected by a bite or sting (this is exclusive to animals). [Source: Wikipedia ]