a protective device for use with a hypodermic syringe for preventing accidental needle sticks after fluid has been ejected from the syringe and rendering the syringe non - reuseable . the protective device comprises a hollow , cylindrical casing defining a forward end wall having an opening therein , a rearward open end and an angular gripping flange adjacent the rearward end . the casing is adapted to be disposed about the syringe such that the syringe is reciprocally translatable therein with the syringe needle projecting through the opening in the forward end wall of the casing and the angular gripping flange axially spaced from the syringe flange . a dual component foaming agent is disposed in the casing adjacent the forward end wall thereof which , when the components thereof are mixed together activate to form an expanding and hardening plastic foam . collapsible tabs are carried by the casing for spacing the syringe from the foaming agent prior to and during ejection of fluid from the syringe to prevent inadvertent activation of the foaming agents . upon pressing the syringe into the casing subsequent to the ejection of fluid from the syringe , the foaming agents are activated and the expanding foam forces the syringe and syringe needle rearwardly within the casing and passes about the needle and through the forward end of the casing and hardens , thereby encapsulating the used needle within the casing and foam .