The invention belongs to methods for production of preparations on the basis of humic substances for protection of the organism from ionizing radiations, and is efficient as a radioprotector and as a therapeutic drug to accelerate excretion of radionuclides and heavy metals from the affected organism. According to the method, an aqueous solution containing humic substances and ammonium molybdate is treated with wave radiation. The quantity of ammonium molybdate is up to 0.4 parts by weight per 1 part of humic substances. Irradiation with waves is conducted until the concentration of the high molecular weight humic substances is brought to a level of 5% or below. The wave radiation is selected in the ultrasonic frequency range from 18 kHz to 66 kHz, with irradiation power density from 0.5 to 5 W/cm 3 , or in the microwave frequency range. from 0.3 to 30 GHz, with irradiation power from 0.5 to 50 kW. For 5 W/cm 3 irradiation at the frequency of 2.45 GHz, the product being treated is maintained at the temperature of 60-70°C for 30 to 90 minutes. Humic substances are produced by oxidation of wood lignin.
