Botulinum toxin is produced by the bacteria Clostridium botulinum. The toxin, delivered by injection, interferes with the communication of nerves and muscles and slightly weakens the muscle. Therefore, botulinum toxin is most often administered in conditions that involve chronic activation of a muscle or a muscle group. Different forms of botulinum toxin are available for medical use. They may not be the same potency and, therefore, not necessarily interchangeable. The form first discovered is Botox®.