The present invention relates to a spray gun for the expulsion of a fluid, with at least one cylinder (1) in which a piston (2) is mounted movably, the cylinder (1) having formed in it a fluid chamber (3), the volume of which can be varied by means of a movement of the piston (2) and in which at least one first cylinder orifice (5) is formed, and a spray orifice which is connected to the first cylinder orifice (5) of the cylinder (1) via a connecting line (20), so that a fluid, which is received by the fluid chamber (3) and is pressed out through the first cylinder orifice (5) by the pressure exerted by the piston (2), arrives via the connecting line (20) at the spray orifice and is expelled there. The spray gun according to the invention is distinguished by the fact that a fluid valve (21) is arranged in the connecting line (20), and, in the cylinder (1) a sensor (29) is provided, by means of which a defined position of the piston (2), in which fluid is still located in the fluid chamber (3) during the expulsion operation, can be detected, and by means of which the fluid valve (21) can be actuated, the fluid valve (21) being closed by means of the sensor (29) when the defined position of the piston (2) has been detected. The invention relates, furthermore, to the use of such a spray gun for the expulsion of plant protectants.