When we think of deadly poisons, most of our minds will jump instantly to arsenic. George III of England, Napoleon Bonaparte and the Gaungxu Emperor of China are all thought to have died from its effects — either from a deliberate assassination or accidental exposure. Just 200 milligrams — around the weight of a raindrop — is enough to kill someone within two hours. The first sign is a metallic taste in your mouth, followed by vomiting and seizures, and death. It sounds horrific — but arsenic is positively innocuous compared to other substances.

Consider tetrodotoxin (TTX), a poison found in puffer fish and blue-ringed octopuses that leaves you paralysed as your body goes through some agonising reactions. “Your lips and tongue will begin to burn, your mouth will erupt with saliva and you’ll get very sweaty,” Dominic Burgess from BritLab explains. “You’ll no longer be able to speak, swallow, seizures will begin and your body will slowly shut down — all while you are completely lucid but unable to move.” Death comes after six hours of symptoms and there is no antidote.

Often these poisons are alarmingly close to home. One lethal chemical — cardiac glycoside digoxin — can be found in a common garden flower, while the deadliest can be seen in many hospitals; just 2 kg would be enough to wipe out the whole of the human race.

Disponível em: www.bbc.com. Acesso em: out. 2016 (adaptado).

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