Mentor Corporation announced that a strain of botulin it is developing to reduce frown lines has entered Phase III clinical trials, which are the large-scale randomized human trials to assess the effectiveness of a medical treatment, compared to the current standard. Like Botox and Dysport, the Mentor product, called “PurTox,” uses a neurotoxin produced by the bacterium Clostriium botulinum. The toxin, which works against wrinkles by paralyzing underlying muscles for a period of about three months, also causes botulism, the food poisoning. Besides its cosmetic uses, it is used as an anti-spasmotic for conditions including Parkinson’s disease, and indeed, Mentor also has a botulinum product in Phase I clinical studies-assessing its safety in a small group of human subjects-aimed at treating pain resulting from from involuntary movements of the head and neck known as cervical dystonia. Mentor Corporation is a Santa Barbara-based Fortune 500 biotech company best known for manufacturing breast implants.