Abstract: A needle stick safety syringe includes a plunger where a concentric coil spring is compressed against the inside front end of the plunger cavity and retained there by a stop which is incorporated at the distal end of the inner cylindrical plunger body. The stop is released when the plunger is pushed all the way forward, which causes the plunger to be engaged with the needle base through interconnecting means. The release is activated by holding the syringe in one hand allowing the needle to be retracted into the cylindrical plunger cavity and to prevent reuse.

Abstract: A needle stick safety syringe includes a outer tubular protective cover or sleeve for the inner syringe body where a concentric coil spring is compressed against the normal flange of the inner syringe body and retained there by a stop which is cantilevered from a collar affixed to the distal end of the inner syringe body. This cantilevered stop also includes a convenient button which may be easily depressed by a finger of one hand holding the outer tubular body to allow the sleeve to be slid over the needle under the bias of the spring. The cantilevered button and stop rides in a groove in the inner diameter of the tubular outer protective body and is captured by a slot which effectively prevents reuse.