The invention relates to a system which can be used for injecting liquids as well as gases, and includes at least: one pipe for inputting gas into the system, with a device controlling the pressure of the input gas； a gas-injection device provided with a means for adjusting a flow of gas to be supplied to a patient, at a predetermined pressure and with at least one flow sensor that determines the exact amount of gas supplied to said patient； a kit for administering gas to the patient； and at least one catheter or needle that can be connected to said administration kit and to the patient, with a drain device arrange between the administration kit and the injection device.
