The Most Poisonous Chemical Compounds

When you get right down to it, everything is poisonous. Water will kill you if you drink too much of it. Oxygen is a deadly poison, yet we need it to live. However, there are some chemicals that we are better off not encountering. Heres a list of the most poisonous chemicals known. Keep in mind, toxicity varies from one species to another (i.e., what may be poisonous for a mouse may be more/less poisonous to a human) and within a species (i.e., age, sex, genetics all affect susceptibility to a toxin). Ive listed the name of the toxin, its source, approximate average lethal dose per kilogram of body weight (LD50), and the species. Tetanus:Â  1 nanogram/kg mouse, humanBotulinal neurotoxin (bacteria):Â  1 nanogram/kg mouse, humanShigella (bacteria):Â  1 nanogram/kg monkey, humanPalytoxin (coral):Â  60 nanogram/kg dog (iv)Diphtheria (bacteria):Â  100 nanogram/kg humanRicin (from castor beans): 1 microgram/kg humanAflatoxins (mold which grows on nuts, legumes, seeds): 1-784 micrograms, depending on type of aflatoxin duckling (oral)Shigella (bacteria) 1 microgram/kg mouseSaxitoxin (shellfish) 3-5 micrograms mouse (iv), about 50x higher dose orallyTetrodotoxin (fugu pufferfish) 10 micrograms mouse (ip)Diphtheria (bacteria) 1.6 milligram/kg mouse Sources Merck Index, 11th Ed., S. Budavari et al. (editors), Merck (1989) ISBN 911910-28-XMcGraw-Hill Concise Encyclopedia of Science and Technology, 2nd Ed., McGraw Hill (1989) ISBN 0-07-045512-0, CD-ROM