botulism is a bacteria that can get into food products. the bacteria produces a toxin that affects the central nervous system causing paralysis and possible death (due to a shutdown of the respiratory system).
The paralytic effects have been studied and have since been utilised by the beauty industry. A dermatologist or plastic surgeon, will inject minute amounts of the toxin directly into muscle tissue (usually in the facial region around the eyes and forehead). the muscles in these areas become paralysed, relax, and reduce facial wrinkles. The effects are temporary, and a new dose needs to be injected every few months or so.
EDIT: Nyaricus beat me to it. damn longwindedness.....