Neurohumoral changes were studied in 431 patients with acute intestinal obstruction and in experiments in 165 small laboratory animals with the model of small intestine ileus. The results were obtained on the basis of estimation of the concentration of catecholamines, acetylcholine-like substances, serotonine, histamine, their metabolism products in blood plasma and of the cardiointervalography data. The neurohumoral changes were shown to appear as early as the initial stage of the disease and to be progressing when the disease period became longer. The prevailing sympathetic activity was dependent on the decreased acetylcholine-like substances in blood plasma and tissues. The serotonine and histamine metabolism changed depending on the stage of the disease.