An auto-injector is provided which includes a housing with a syringe slidably received therein. The syringe has a barrel with a piston movable therein and a needle extending therefrom. The piston is releasably secured to one end of a plunger which is slidably secured within a body in the housing and is operable through a bias provided by a motive source. In use, the plunger moves under the bias from a loaded condition to a discharged condition to move the syringe so that the needle extends from a tip at an injection end of the housing and to slide the piston within the barrel to expel the contents of the syringe. The plunger is held in the loaded condition against the bias by a detent extending from the body and which can be selectively released by operation of an actuator when pressure is applied to the tip.
