A manually driven syringe for injecting fluids under high pressure is described that includes a barrel (12), a plunger (13) that is received within the barrel and extends rearwardly through an aperture (28) in the body (27) of a handle (14) which carries a pair of opposed finger grips (19, 22). The finger grips are located rearwardly of the barrel and laterally of the shaft (19) of the plunger, elongated so as to each accommodate two fingers, and angled rearwardly. This design minimizes the distance between (a) the inner edges of the grips and (b) the grips and the head of the extended plunger, thus making the syringe easier to grip in the palm of the hand and enabling the syringe to be gripped strongly between the fingers and the palm.