Botulinum toxin is a protein and neurotoxin produced by the bacterium Clostridium botulinum. It is the most acutely lethal toxin known, with an estimated human median lethal dose (LD-50) of 1.3–2.1 ng/kg intravenously or intramuscularly and 10–13 ng/kg when inhaled. Botulinum toxin (BTX) can cause botulism, a serious and life-threatening illness in humans and animals.
