Abstract: A safety syringe is disclosed. A plurality of axial slits are formed in the outer wall of the unidirectional buckling chamber of the seat. An inner wall of the unidirectional buckling chamber has a second unidirectional buckling lip. A buckling head at a front end of the rod head of the push rod is installed with a unidirectional buckling lip; the third unidirectional buckling lip is installed with a plurality of slits so that the third unidirectional buckling lip is elastic. Thereby, by the axial slits of the unidirectional buckling chamber and the slits of the third unidirectional buckling lip, when the push rod is pushed to a foremost end, the buckling head at the front end of the rod head is pushed into the unidirectional buckling chamber at the rear end of the rod head of the push rod.

Abstract: A syringe includes a needle support received in a front portion of a housing and having a front tube for attaching a needle. A plunger includes a piston slidably received in the housing and a stem detachably secured to the piston. The piston may be secured to the needle support for pulling the needle into the housing after use. The needle support has one or more bulges for engaging with juts of the housing for limiting the needle support to rotate relative to the housing. The piston includes a rod and a pole for adequately forcing medicine out of the needle support.