Botulinum toxin is a substance produced by the bacterium *Clostridium botulinum*; the toxin causes the disease known as botulism. People often contracted it by consuming improperly processed meat products.
The toxin blocks the transmission of nerve signals to the muscles. When a small amount is injected into the muscles, it causes muscle paralysis (lasting about three months) and smooths out facial wrinkles (as the muscle relaxes and stops pulling on the skin to which it is attached); it also reduces sweating by preventing the activation of sweat glands.
Botulism is caused by systemic intoxication with botulinum toxin; symptoms include:
- blurred or double vision, drooping eyelids dry mouth
- difficulty speaking and trouble swallowing
- facial muscle weakness and the progressive spread of weakness—from the neck, torso, and arms down to the lower limbs
The administration and correct dosage of botulinum toxin constitute a medical procedure that must be performed by a physician.