Clostridium botulinum is an anaerobic, endospore-forming bacterium in the family Clostridiaceae and the causative agent of botulism, a potentially fatal neuroparalytic illness caused by its potent botulinum neurotoxin — the most acutely toxic substance known. The neurotoxin acts by blocking acetylcholine release at neuromuscular junctions, causing flaccid paralysis and potentially respiratory failure. Seven serologically distinct toxin types (A through G) are produced by different strains, with types A, B, E, and F responsible for human botulism occurring through foodborne intoxication, wound infection, and infant intestinal colonization. C. botulinum spores are ubiquitous in soil and sediments worldwide, resisting boiling for extended periods and requiring autoclaving to destroy. Home-canned low-acid foods provide ideal anaerobic, low-acid conditions for germination and toxin production. Paradoxically, purified botulinum toxin has extensive medical applications, used clinically to treat spasticity, hyperhidrosis, chronic migraine, and cosmetically to reduce facial wrinkles (Botox). Strains are distributed globally and isolated from soils, sediments, and animal intestines across all continents.