A method is provided for rinsing and/or filling a blood treatment device, in particular for priming such a device. The blood treatment device includes at least one membrane filter, in particular a hollow fiber membrane filter, at least one first partial circuit, and at least one second partial circuit, with the first and second partial circuit being separated by the membrane filter in a semipermeable manner. The first partial circuit is first filled with a fluid with a uniform and/or a pulsatile first volumetric flow rate that does not exceed a specified threshold value. At this value the fluid has not yet completely wetted and/or soaked the membrane, and/or the second partial circuit is at least temporarily open towards the atmosphere, and air is displaced from the first into the second partial circuit via the membrane filter, and/or during filling no negative pressure is applied to the first partial circuit.
