Abstract: A prefillable type of hypodermic syringe assembly is disclosed herein. This assembly utilizes an open-ended glass barrel in combination with a rubber sealing bung located across the front end of the barrel and a rubber plunger slidably disposed within the barrel behind the sealing bung so as to define an internal medication chamber. In this way, medication stored within the chamber comes in contact with glass and rubber only until the syringe assembly is used. At that time, a syringe needle is placed in fluid communication with a cooperating opening through the sealing bung which serves to pass medication from the internal chamber to the needle. Until the syringe assembly is used, the sealing bung is maintained in a collapsed condition to close its through opening, thereby ensuring that only rubber and glass come in contact with the stored medication.