Legally and in hazardous chemical labelling, poisons are especially toxic substances; less toxic substances are labelled “harmful”, “irritant”, or not labelled at all.
In medicine (particularly veterinary) and in zoology, a poison is often distinguished from a toxin and a venom. Toxins are poisons produced via some biological function in nature, and venoms are usually defined as biologic toxins that are injected by a bite or sting to cause their effect, while other poisons are generally defined as substances which are absorbed through epithelial linings such as the skin or gut.
Poisons are an invaluable part of an assassins repiture. Poisons have been used countless times throughout history as a hard-to-trace and effective form of stealth execution. These books detail a number of poisons that are available in the public domain and additionally a number of improvised homemade poisons. Learn how to make poisons.
