The efficacy of functional food was evaluated in general embodiment diet of cardiological hospital in patients receiving oxygen-containing products (oxygen smoothies) based on protein-carbohydrate raw materials (dairy whey) with dietary fiber. 60 patients were included in local open, prospective, parallel-group study; among them 36 men and 24 women aged 60-75 years, meeting the following criteria: patients with chronic heart failure I-IV functional class, are hospitalized in the cardiology department, have no contraindications to enteral oxygen therapy and sign an informed consent form. The main group comprised 30 patients, which along with standard therapy received enteral oxygen therapy. 30 patients from the control group received standard therapy and aerated non-oxygen mixture (placebo). Standard therapy included cardioprotective drugs, diuretics and concomitant therapy (enzyme preparations) depended upon the clinical status of the patient. Patients received 500 ml of a cocktail within 10-15 minutes daily for 10 days for 1-1,5 hours before the main meal. The studies revealed the most pronounced clinical effect of enteral oxygen therapy in relation to clinical symptoms and side effects caused by drug administrations. After 3-4 procedures patients with chronic heart failure treated with enteral oxygen therapy had a decrease in fatigue, increase physical performance, improve appetite, emotional lability. By the end the positive dynamics of oxygen therapy on the above grounds was detected in 90% of patients. Monitoring pulse oximetry showed a significant increase of oxygen saturation as a result of the course of enteral oxygen therapy: oxygen saturation increased from 98.13 ± 0.13 to 99.17 ± 0.13% (p < 0.001) while in the control group from 98.12 ± 0.20 to 98.19 ± 0.19% (p < 0.01). Physical activity increased from 318 ± 15 to 389 ± 13 m (p < 0.001), in the control group--from 331 ± 17 to 362 ± 15 m (p < 0.05) in the main group on the test results with the 6-minutes walk test. In the main group dyspnea Borg changed from 11 to 7 scores as compared to the control group--from 11 to 9 scores. Analysis of the results showed the advisability of incorporating developed oxygen-containing products in diet therapy of cardiac patients to reduce the severity of side effects from taking of drugs administration to normalize the process of digestion, to improve the overall health of patients.