What Are the Most Deadly Poisons and Chemicals?

Any chemical becomes poison if you are exposed to enough of it and in the wrong way.
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This is a list or table of chemicals that can kill you. Some of these poisons are common and some are rare. Some you need in order to live, while others you should avoid at all costs. Note that the values are median lethal values for an average human. Real-life toxicity depends on your size, age, gender, weight, route of exposure and many other factors. This list just offers a glimpse at a range of chemicals and their relative toxicity. Basically, all chemicals are poisonous. It just depends on the amount!

List of Poisons

This table is organized from least deadly to most deadly:

Chemical Dose Type Target
water 8 kg inorganic nervous system
lead 500 g inorganic nervous system
alcohol 500 g organic kidney/liver
ketamine 226 g drug cardiovascular
table salt 225 g inorganic nervous system
ibuprofen (e.g., Advil) 30 g drug kidney/liver
caffeine 15 g biological nervous system
paracetamol (e.g., Tylenol) 12 g drug kidney/liver
aspirin 11 g drug kidney/liver
amphetamine 9 g drug nervous system
nicotine 3.7 g biological nervous system
cocaine 3 g biological cardiovascular
methamphetamine 1 g drug nervous system
chlorine 1 g element cardiovascular
arsenic 975 mg element digestive system
bee sting venom 500 mg biological nervous system
cyanide 250 mg organic causes cell death
aflatoxin 180 mg biological kidney/liver
mamba venom 120 mg biological nervous system
black widow venom 70 mg biological nervous system
formaldehyde 11 mg organic causes cell death
ricin (castor bean) 1.76 mg biological kills cells
VX (nerve gas) 189 mcg organophosphate nervous
tetrodotoxin 25 mcg biological nervous system
mercury 18 mcg element nervous system
botulinum (botulism) 270 ng biological nervous
tetanospasmin (tetanus) 75 ng biological nervous system

Poisons: Lethal vs Toxic

Looking at the list of poisons, you might be tempted to think lead is safer than salt or bee sting venom is safer than cyanide. Looking at the lethal dose can be misleading because some of these chemicals are cumulative poisons (e.g., lead) and others are chemicals your body naturally detoxifies in small amounts (e.g., cyanide). Individual biochemistry is also important. While it might take half a gram of bee venom to kill the average person, a much lower dose would cause anaphylactic shock and death if you're allergic to it.

Some "poisons" are actually necessary for life, such as water and salt. Other chemicals serve no known biological function and are purely toxic, such as lead and mercury.

Most Common Poisons in Real Life

While it's unlikely you'll be exposed to tetrodotoxin unless you eat improperly prepared fugu (a dish prepared from pufferfish), some poisons routinely cause problems. These include:

  • Pain medicine (over the counter or prescription)
  • Sedative and antipsychotic drugs
  • Antidepressants
  • Cardiovascular drugs
  • Household cleaners (particularly when they are mixed)
  • Alcohol (both grain alcohol and types not intended for human consumption)
  • Pesticides
  • Insect, arachnid, and reptile venom
  • Anticonvulsants
  • Personal care products
  • Wild mushrooms
  • Food poisoning