Abstract: The invention relates to a system for injecting a fluid through or into human skin, optionally by needle-free injection or by injection with a needle, comprising (A) a single-use syringe (10) comprising an ampule body (12) forming a chamber for accommodating the fluid to be injected, arranged within the chamber, an axially displaceable, sealingly guided ampule piston (16) and an external taper (18) of a Luer cone at the distal end of the ampule body (12); (B) an adaptor (30) comprising an internal taper (32) of a Luer cone at the proximal end of the adaptor (30) and an exit aperture (36) for the fluid to be injected needle-free at the distal end of the adaptor (30) and (C) an autoinjector comprising a receptacle device (50) for the coupled and fluid-filled combination of a single-use syringe (10) and an adaptor (30), which is configured to maintain the form-fit between the single-use syringe (10) and the adaptor (30) and to support the ampule body (12) of the single-use syringe (10), distally arranged a sk