Abstract: A self-sealed hypodermic syringe uses Louis Pasteur's principle of the "tortuous path" to maintain a sterile condition within a medicament chamber contained within the syringe barrel without using airtight seals. A double walled stem cooperates with the barrel to form a rear tortuous path. A needle and hub assembly cooperates with a front bore in the barrel together with an overlying needle sheath and front cap to form a front tortuous path. The front and rear tortuous paths are maintained by a breakable bond between the cap and the stem until the syringe is to be used. Another embodiment includes a pin on the front cap which cooperates with the front barrel bore in place of the needle and hub assembly.