Abstract: An improved apparatus (10) is made available for separating at least two biological substances in solution by adsorption and comprises in the upper interior section (28) of its housing (10) a means effecting a partial constriction of the cross-section of said interior section (28), said section thereby being divided into an upper and lower subspace (34; 36), and which is further distinguished in that the upper subspace (34) and the lower subspace (36) are in flow connection with each other both as regards the solution to be separated and the adsorption agent particles, the feed tube (40) for the solution to be separated being arranged in such a manner that the discharge of the solution to be separated takes place in the lower subspace (36), and the apparatus is a self-contained in unit in sterile form.