Abstract: In order to separate viruses from protein solutions, particles of a solid phase are suspended in said protein solution. The solid phase is an adsorbent chosen from the group kieselguhr, silicic acid, clay minerals, metal hydroxide or oxihydrate, cellulose, perlite, and water insoluble synthetic polymers. Subsequently the solid phase together with the viruses that have adsorbed to it is separated from the fluid phase. The protein solution is brought into contact at least once with the solid phase for at least 10 minutes during which time a suspension is formed; subsequently the solid phase is separated from the liquid phase.