Abstract: A use of beta-glucan in order to increase anti-tumor immunity in remission after the treatment of solid tumors, where after the long-term peroral usage the concentration of the CD8+ Lymphocytes, CD19+ lymphocytes increases and the level of IgG3, IgA, CD16+56+ increases. The clinical study has shown the efficiency of the preventive treatment during the immunosensitive cancer such as breast cancer. In the preferable arrangement beta-glucan is fungal ? (1,3/1,6) glucan prepared from the oyster mushroom. During the sequential usage in the first phase a high dose of beta-glucan is used and in the second phase a low dose of beta-glucan is used. The high dose of beta-glucan is at least twice the low dose of beta-glucan. The administration is long-term and continuous without sequences where the dosage is completely omitted. The daily high dose of beta-glucan range from 600 mg to 800 mg.