Abstract: A method for separating eucaryotic or procaryotic cells or other particularly biological material which is sensitive against high shearing forces from a suspension is provided using at least one hydrocyclone with an inlet and an outlet. The outlet of the hydrocyclone is essentially opposite to the inlet and the interior space of the hydrocyclone converges towards the outlet. The suspension is delivered to the inlet of the hydrocyclone, and the suspension enriched with the cells is drained off from the outlet. The enriched suspension is then guided from or through the outlet by a flow means in such a way, that a minimum of shearing stresses occurs and the kinetic energy of the enriched suspension at the outlet of the hydrocyclone is reduced that the viability of the cell material is influenced at a minimum.