A flushing system for a catheter, in particular for a catheter of a catheter pump, comprising a supply line having a pump section, a discharge line having a pump section and a pump, wherein the diameter of the pump section of the discharge line is smaller than the diameter of the pump section of the supply conduit, the pump interacts with the pump section of the supply line for supplying flushing fluid to the catheter, and the pump interacts with the pump section of the discharge line for discharging flushing fluid from the catheter.