Abstract: A syringe having a plunger lock, the syringe comprising a syringe body having an open rear end, a plunger lock provided adjacent the open rear end, the plunger lock comprising at least one catch member having a portion extending partially into the open rear end of the syringe body and adapted to catch a portion of the plunger when the plunger has been pushed to the front of the syringe barrel, the plunger having a front end formed with a seal, and a rear end, and a projection adjacent the rear end which can ride underneath the at least one catch member when the plunger is inserted into the syringe barrel but which catches against the catch member upon attempted retraction of the plunger from the syringe barrel.