In contrast to the classic, slowly progressive polyneuropathy in alcoholic patients, acute forms, clinically mimicking Guillain-Barré syndrome, are rare. We present a patient who developed motor weakness and sensory loss in all four limbs within four days. Laboratory data were consistent with long-term alcohol abuse and documented thiamine deficiency. Repeated cerebrospinal fluid examinations were normal. Electrophysiological studies showed an acute sensorimotor polyneuropathy with predominantly axonal involvement. We conclude that acute alcoholic neuropathy has to be distinguished from Guillain-Barré syndrome and other forms of acute polyneuropathy by using clinical, laboratory, and electrophysiological data. Both ethanol toxicity and vitamin deficiency could play a role in the pathogenesis.