Abstract: A disposable syringe has a plunger rupture device and a washer-guide sealing barrel nozzle which make it safe against re-use, since the plunger breaks up and the piston is stuck at the bottom of the barrel, thereby making impossible reloading of the syringe. The syringe is assembled by fitting the pressure washer onto the plunger, fitting the rubber to the piston base, fitting the plunger to the piston, inserting the support bolt to the fitting of the set plunger/piston, fitting the assembled set plunger/piston into the barrel, and, finally, seating the screening washer inside the top of the barrel, thereby sealing the syringe entirely.