In the biological industry, cultures of human and animal cells are used, on the basis of which there receive means of protection and prevention of various diseases. Moreover, the drugs themselves can be potential sources of infection for living biosystems. During cell cultivation, nutrient media are used, the obligatory component of which are animal blood serum. The disadvantages of sera include the inconstancy of their composition, due to the age of the animals, their feeding and time of year of receipt of serum. It is a generally recognized fact that sera may are contaminated with various microorganisms with which they contaminate cell cultures, and, consequently, the final product obtained on their basis. It is generally accepted that the most effective way of serum decontamination is micro- and ultrafiltration. But they are not obstacle for viruses, mycoplasmas, nanobacteria, and others. We have developed a method for purifying blood serum using an aqueous extract of shungite containing lanthanides. The purification mechanism is due to the fact that highly reactive lanthanide cations interact with structures containing a nucleic component. The selective interaction of lanthanides is accompanied by the formation of complexes with the inclusion of structures containing DNA or RNA, which are then easily removed by separation or microfiltration