Background. The efficiency of the application of normobaric interval hypoxic therapy and enteral oxygen therapy for the treatment of the patients suffering from chronic obstructive pulmonary disease remains to be confirmed. Aims. The objective of the present study was the identification of the pathophysiological mechanisms responsible for the efficiency of normobaric interval hypoxic therapy and enteral oxygen therapy in the patients presenting with a chronic obstructive pulmonary disease. Material and methods. A total of 230 patients at the age from 45 to 60 years were examined. All of them presented with chronic obstructive pulmonary disease (COPD). 150 patients were given a course of normobaric interval hypoxic therapy and enteral oxygen therapy while the remaining 80 ones constituted the control group. Results. It was shown that the combined application of normobaric interval hypoxic therapy and enteral oxygen therapy provided an effective tool for the correction of the health status in the patients with chronic obstructive pulmonary disease. This method allowed to improve arterial blood supply with oxygen, increase the blood hemoglobin level and its oxygen capacity, augment oxygen tension and content in the arterial blood. The combination of the intake of oxygen cocktails and hypoxic therapy resulted in the improvement of metabolic processes in the lungs manifested as the alteration in the characteristics of the condensate of the exhaled air. The decrease in the content of malondialdehyde gave evidence of the reduction of lipid peroxidation while the enhanced activities of glutathione peroxidase and superoxide dismutase in blood confirmed the activation of the antioxidant system. The improved oxygen supply at all stages of its mass transfer along with the resulting improvement of oxygen utilization by the tissues was responsible for the reduction of hypoxia in the bronchial tree and lung tissue. Conclusions. The present study confirmed the high effectiveness of the combined application of normobaric interval hypoxic therapy and enteral oxygen therapy for the rehabilitation of the patients presenting with chronic obstructive pulmonary disease.