The effects of ethanol intoxication on the hippocampus (H) has been studied in 18 (5 died) Sprague-Dawley rats (group A), 5 other rats served as control (group C). The weight of the animals at the beginning of experiment was 135-140 g and, at the end, 234 g for group A and 240 g for group C. Both groups were given a liquid diet. In group A, the ethanol provided 36% of the total calories; in group C these calories were supplied as dextrin-maltose. The average of the diet alcoholemia was 159.6 mg/100 ml. After 70 days of alcohol intake, the rats were transcardially perfused, and brain and liver were removed. The liver of the alcoholic rats exhibited an intense steatosis, and the H showed important modifications in number of neurons as well as in nuclear size. The neuron loss in group A, with respect to group C was: highly significant (P less than 0.001) for CA2; very significant (P less than 0.01) for CA3 and CA4; in CA1 and GD the reduction was not significant. In spite of neuron loss, the nuclear area showed a reduction in size: highly significant in CA2 and CA4; very significant in GD, but in CA2 and CA3 the reduction did not reach statistical significance. These results confirm the lethal influence of ethanol on some neurons, and the limited ability of the remnant neurons to compensate for neuronal loss.