Abstract: A device for protectively sheathing a syringe and hypodermic injection element, which device includes a tubular sheath having a syringe barrel reciprocably mounted within the tubular sheath for coaxial movement. The barrel carries a plunger for ejecting a liquid from a spout or tip on one end of the barrel. The sheath near one of its ends, carries a locking element, and the barrel, adjacent its end through which liquid is ejected upon reciprocation of the plunger, carries a cooperating locking element which interlocks with that locking element carried by the sheath when the barrel is withdrawn into the sheath to a location where the barrel tip through which liquid is ejected is totally encased and protected within the sheath, as is any hypodermic injection element which is carried on the tip of the barrel.