The present invention is particularly relates to medical pumps used for water jet surgery, connectivity is improved and the operation of the pump between the pump unit and the pump drive unit is simplified. To this end, the medical pump includes a pump unit for moving in a cylinder associated with the piston comprises at least one piston, a pump drive device. The pump drive device, the pump unit, and can be opened and closed gripping device for desorption or from the pump drive unit is mounted on the pump drive device, the pump unit, or connected to the pump drive or and closable coupling device for coupling released from the pump drive unit, driven by the gripping device and / or capable of controlling the coupling device ways, as the operating state or a standby state is created, to be particularly open and / or closed at least one drive means, and a control system for driving the pump unit by moving the piston, which is communicably connected to the detecting means to the inlet of the control system, the pump unit and the pump drive unit detecting the insertion state defining a predetermined relative position between the first detection signal indicating that the pump unit is present in the pump drive unit, to transmit to said control system for controlling the driving means and a configured detection means. Control system for processing the first detection signal is configured to control the drive means to produce said operating state.