Experiments involving chronic introduction of ethanol (36 per cent of caloric value) as a part of a specially devised liquid ration demonstrated the trainability of rats to sharply decrease, their antistress resistance to significantly decline, especially in rats kept on a low-protein diet. A general tendency toward a reduced activity of acetylcholinesterase in different sectors of the brain was revealed both in animals receiving alcohol against the background of a normal protein allowance and in those kept on a low-protein diet (when compared with the enzyme activity in animals maintained on a ration with a normal of protein).