The invention relates to a method of purging gas bubbles from at least one target zone of an extracorporeal blood circuit, preferably of an extracorporeal blood circuit of a dialysis machine, with a flushing liquid, wherein the flow rate and/or the pressure of the flushing liquid in the extracorporeal blood circuit is/are inconstant at least at times during the flushing process; and/or wherein the flow rate of the flushing liquid in the extracorporeal blood circuit lies above a range of possible flow rates at least at times during the flushing process, which range is used during the treatment for the blood. The invention furthermore relates to an extracorporeal blood treatment unit having an extracorporeal blood circuit, a pump and a control unit, with the control unit being configured to carry out a flushing process in accordance with the invention. The invention furthermore relates to an extracorporeal blood treatment unit having an extracorporeal blood circuit, a pump and a control unit, with the control unit being configured such that the conveying speed for blood is slowly increased after a standstill of the pump or after an operation of the pump at throttled speed.