A subacute form of encephalopathy was observed in 7 patients with a history of severe chronic alcoholism. These episodes lasted about 1 to 6 weeks and were characterized by epileptic seizures (grand mal, focal motor), prominent EEG abnormalities with focal features (slowing, spiking, "PLEDs") and neurological deficits such as hemianopsia or hemiparesis. These changes resolved with symptomatic (mainly anticonvulsive) treatment but recurrences occurred in 3 cases. The clinical picture does not fit any of the known CNS complications of chronic alcoholism and there seems to be no relationship to alcohol withdrawal. Impressive EEG abnormalities strongly differ from the mild abnormalities or normal tracings found in other CNS complications of alcoholism. The pathogenetic mechanisms are essentially obscure; vascular changes might play a contributory role in some of the cases.