Abstract: A syringe assist device including a frame and moveable carriage that are respectively attached to a conventional syringe and its plunger. The frame has a toothed rack and the carriage contains a force amplifying gear and lever mechanism. A thumb ring transmits the force applied by the user's thumb to the lever to rotate the gear and move the carriage along the frame. This action in turn applies amplified compression to the syringe plunger. A ratchet connection between the lever and the gear enables the movement of the carriage to be continued without force amplification when the lever has reached the end of its stroke.