Abstract: A needleless injector includes an injector body having first and second opposite ends. There is a first piston disposed within the body. A second piston may also be disposed within the body configured with a second end for housing a nozzle. There is a medicine inlet for receiving medicine and a pressurized fluid inlet for receiving pressurized fluid. There is also a trigger for releasing the pressurized fluid to drive the first piston thereby driving the medicine through the nozzle for needleless delivery.