The benzodiazepine/GABA (gammaaminobutyric acid) receptor complex was investigated during severe ethanol intoxication and withdrawal in the rat. The intragastric intubation technique was used to establish physical ethanol dependence in the animals. Cerebral cortex from male Wistar rats was studied 1) after 3 1/2 days of severe ethanol intoxication, 2) during the ethanol withdrawal reaction and 3) in a control group. The effect of GABA-ergic activation by muscimol and THIP (4,5,6,7-tetrahydroisoxazole(5,4-c)pyridin-3-01) on 3H-diazepam binding was unchanged during ethanol intoxication and withdrawal, as was the affinity constant (KD) and the maximal number of binding sites (Bmax) for 3H-flunitrazepam. In conclusion, the benzodiazepine/GABA receptor complex is unlikely to play any causal part in physical ethanol dependence.