A compressed gas motor. The motor has a port and a hollow cylinder delimited by a wall with a ventilation opening, a rear closure, and a plunger axially movable in the cylinder. The plunger divides the cylinder into front and back chambers. The ventilation opening is periodically opened towards the back chamber during operation of the motor by movement of the plunger. A compression spring in the front chamber urges the plunger towards the rear closure and/or a tension spring in the back chamber draws the plunger towards the rear closure so that the back chamber is closed relative to the ventilation opening by the plunger and the back chamber is connected with the port when the same pressure prevails in the front and back chambers. The motor can be used in surgical drive systems, medical lavage systems and medical devices. Also disclosed is a method for operating the motor.