The FDA has issued an "early communication" about the risk of botulism toxicity in people using botulinum toxin type A (Botox, Botox Cosmetic), and botulinum toxin type B (Myobloc). Botox Cosmetic is approved to temporarily reduce the appearance of moderate to severe facial wrinkles. Myobloc is approved to treat cervical dystonia in adults. Botox is approved to treat cervical dystonia and several other conditions, such as blepharospasm (eyelid spasms). All these drugs use botulinum toxin to paralyze nerves and relax muscles.

Normally, the drug exerts only local effects. But in rare cases, the toxin spreads to other parts of the body. Paralysis of muscles used for respiration or swallowing can be fatal.

The most serious reports linked to botulinum injections involve children with cerebral palsy being treated for limb spasticity. Botulinum toxins aren't FDA-approved to treat limb spasticity or for any condition in children under age 12.

Teach a patient receiving botulinum toxin for any reason to immediately seek medical care if she experiences signs and symptoms of botulism, such as difficulty swallowing, talking, or breathing; slurred speech; muscle weakness; or difficulty holding up her head. These effects have been reported as early as 1 day and as late as 1 week after treatment.