Abstract: The invention relates to a sterile sheath for an injection syringe to guarantee sterility for a product which has been taken up by the injection syringe. The sterile sheath includes a sealable casing made of plastic and an output connection piece, the interior of the sheath serving to receive the injection syringe. The injection syringe can be connected to the output connection piece, which is provided with a valve whose direction of flow is exclusively from the injection syringe to the exterior. Owing to the valve, no microorganisms are able to ascend from the exterior into the syringe.