By method of scanning electron microscopy erythrocyte structure was studied in rats in carbophos poisoning. Following up to 76% acetylcholinesterase inhibition with distinct symptoms of intoxication nearly 30% of erythrocytes were deformed and tended to aggregate. Observation of blood circulation in vessels of pia mater revealed formation of erythrocyte conglomerations in vascular bed. Erythrocytes get stuck in small vessels, disturbing blood microcirculation. Supposedly, obstruction of the smallest vessels with conglomerations is one of the reasons of exotoxic shock development and low efficiency of treatment of carbophos poisoning by means of specific antidotal cholinolytic drugs and cholinesterase reactivators.