A 30-year-old male drug abuser developed ophthalmoplegia, bulbar paralysis, and limb weakness responsive to edrophonium. However, potentiation of a low-amplitude evoked muscle action potential was produced with repetitive nerve stimulation at 10 Hz, and the clinical and electrophysiological data suggested the diagnosis of botulism. The source of botulism type B toxin was a clinically obscure cyst produced by subcutaneous infiltration of cocaine two weeks prior to the onset of symptoms. The patient improved with chronic administration of pyridostigmine bromide and plasmapheresis. Wound botulism may be underdiagnosed because of confusion with inflammatory neuropathy or myasthenia gravis. Neuromuscular transmission studies in patients with acute craniosomatic paralysis can prevent such oversights.