Abstract: Universal safety syringe having a protective cap, a cylinder, a plunger and a cannula mounted on a cannula base, it being the case that the cannula base is designed such that it can be pushed firmly against a stop in the protective cap, that the protective cap, which can be pushed externally onto a cone, corresponding to a Luer cone, of the cylinder, is provided with a narrowed section, which is provided on the inside of the cap, in front of a recess designed for receiving the cannula base, and delimits the push on travel, that a recess which receives a cannula base is provided with an undercut which prevents the cannula base from being removed in the forward direction, and with an undercut of which the effect can be overcome by the cone being widened from the inside and which is provided for safeguarding the cannula stop from being pushed in unintentionally during insertion of the syringe, and it also being the case that the plunger is designed with a section which widens the cone cylindrically and with a mu