Abstract: For separating non-conventional transmissible agents (NCTAs), i.e. causative agent(s), of transmissible spongiform encephalopathies (TSEs) from a solution of a protein susceptible to contamination with NCTAs, particularly from blood products, at least one adsorbent is suspended, for a time of at least 10 minutes. The absorbent is selected from kieselguhr, diatomaceous earth, silicic acid, clay minerals, metal hydroxide, metal oxihydrate, cellulose, perlite, bentonite, and water-insoluble synthetic polymers. The obtained suspension is agitated, and subsequently the adsorbent is separated from the protein solution.