Abstract: The present invention typically is in the form of a needleless injector which includes the following components: (1) a needleless syringe installed in the injector for holding medication prior to injection, the syringe including an injection aperture at the forward end thereof; (2) a syringe plunger slidably mounted to the rear end of the syringe for forcing medication out the syringe aperture; (3) a syringe plunger drive mechanism providing power to drive the syringe plunger and thereby force medication out of the syringe; and (4) a syringe drive control mechanism for controlling the operation of the drive mechanism, the drive control mechanism including a warning system which warns the user if a pre-injection condition is not met, an interlock system which prevents injection from taking place if the pre-injection condition is not met, and a sensing system which senses whether the pre-injection condition is not met and conveys a signal to the warning and interlock systems informing as to whether the pre-inje