Question: What is the most lethal poison?

Sarah Martin answered on 19 Jun 2012:

Hi meg!

It’s Botulinum, a toxin that is a protein produced by the bacterium Clostridium botulinum. It is the most acutely toxic substance known! The lethal dose is only one nanogram per kilogram body weight (so that’s one millionth of a gram!). So four kilograms would be enough to kill all humans on the planet!

Botulin numbs our nerves and stops our muscles working, and that stops us breathing and our heart beating. It’s a pretty horrible way to die.

Botulin is used however lots in medicine in very small doses – you’ve probably heard of botox treatments? Cosmetic surgeons use very very small quantities to inject into vain people’s faces to stop their muscles working and them getting wrinkes. But it’s also used to treat people who suffer from debilitating cramps!

Great question again!
🙂 Sarah