The present patent application describes a stirrer comprising a combination of at least one axially-conveying element and at least one radially-conveying element relative to the rotary shaft of the stirrer wherein the largest diameter of the at least one axially-conveying element is equal to or less than the inner diameter di of the radially-conveying element. In one embodiment the stirrer according to the invention is a combination of one anchor stirrer with at least one inclined-blade stirrer. Furthermore the use of the stirrer according to the invention for the culture of cells in a dialysis method is described.