Whoever had the idea to squirt botulism into someone’s face to cure wrinkles? 
Does it really sound that much crazier than using bread mold to fight infection? Naturally it’s not as simple as directly injecting improperly preserved foods.
Dr. Amir Karam of Carmel Valley Facial Plastic Surgery explains, “Botox® Cosmetic is a purified protein produced by the Clostridium Botulinum bacteria that decreases the activity of wrinkle-forming muscles.” The use of this protein started out as a treatment for muscle spasms. Like so many other discoveries, the protein’s usefulness in treating wrinkles was noticed as a side effect.
The botulinum protein works by blocking the receipt of neurotransmitters by nerve terminals responsible for the wrinkle-causing muscles. A Botox® injection technique using just a few drops with a small needle is enough to be effective for several months.
via DrKaram.com