Abstract: A dose metering device for use with a syringe comprises a fixed screwthreaded member (17) which is either integral with or fixed in use to the cylinder (10) of the syringe and is in threaded engagement with a screwthreaded plunger (13) which can be rotated by a manually-rotatable cap (30) acting through a ratchet and pawl mechanism (32, 34) whose ratchet wheel (26) drives a driving rod (24) which is slidably keyed to the plunger (13). The plunger engages the piston or plug (11) of the syringe. A stop (42) limits rotation of the cap (30) which can be turned away from the stop through a variable angle to a selected angular position shown on a scale (39) of volumetric dose units, the pawl (32) overriding the ratchet teeth (34), to preset a dose to be expressed.