Botulism is both an old and an emerging disease. Over 100 years ago, the classic food-borne type was found to be caused by ingesting contaminated food containing the toxin produced by a bacteria. In the first half of the 20th century a second form, wound botulism, was discovered. Three additional forms (infant, hidden, and inadvertent) were first described in the last quarter of the 20th century. Our understanding of how botulinum toxin blocks the release of acetylcholine at the neuromuscular junction has been clarified in the past 10 years. In the past 20 years, we have witnessed one of the strangest of all ironies in the history of medicine. The very lethal botulinum toxin is now being used as a treatment in an expanding list of disorders. Research is advancing in several directions. These new avenues include improved methods of preventing and treating botulism and additional novel uses of botulinum toxin as a therapeutic agent. In this article, the five clinical forms of botulism, the actions of botulinum toxins, electrodiagnostic methods, treatments, and possible future directions are discussed.