Abstract: A device for expelling fluid from a pre-filled vial includes a hollow needle that is axially mounted on a syringe body. A guard, also mounted on the syringe body, is moveable between a first position wherein it is held to expose a distal portion of the needle and a second position wherein, after being released, it covers the distal portion. In operation, the vial is engaged in fluid communication with the needle, and it is then advanced on the syringe body. During this advancement, fluid is expelled from the vial through the needle, and the vial releases the guard for its movement from the first to the second position.