FIELD : medicine.SUBSTANCE : invention relates to medicine and concerns a method for suppressing cancer metastasis, characterized by a patient with a diagnosis of cancer receives a sample of his biomaterial containing tumor cells. Then the tumor cells are isolated from the obtained sample with the release of the supernatant from them, that is then cultivated in the culture medium of the following composition : DMEM/F12 1 : 1 medium with HEPES supplemented with 2 mmol/ml or 3.65 mg/10 ml L-glutamine, 100 units/ml penicillin, 100 mcg/ml streptomycin, 10?% fetal serum, at T=37?°C and 5?% CO2 within 48–72 h. Then the exosome-containing precipitate is separated from the obtained culture medium, dissolved in phosphate-saline buffer in a ratio of 1 : 5–1 : 20, and then the resulting solution is administered orally to the patient.EFFECT : invention provides an increase in the effectiveness of treating patients with a diagnosis of cancer.4 cl, 1 ex