A disposable syringe for use in a needleless injector includes a tubular body with an open rear end, a closed front end containing an injection orifice, a chamber in the body for receiving a liquid and a plunger slidable in the chamber for pushing the liquid out of the orifice. A tip is provided on the inner end of the plunger for separation from the remainder of the plunger to block the orifice when the plunger is retracted after an injection, whereby the syringe cannot be re-used.
