An injection device (10) for administering a liquid has a barrel (12) with an outlet (20) for the liquid, and a piston (14) arranged in the barrel (12). The piston is designed to force the liquid out from the outlet (20) by displacement into the barrel (12). The injection device (10) has an overpressure protection with a sensor (24) and with an actuator (26). The sensor (24) detects the pressure of the liquid in the barrel (12) directly or indirectly. The actuator (26) prevents a further increase in the pressure of the liquid.