Abstract: A medical syringe having a disposable capsule, or capsule, containing the needle and the injection fluid, the syringe including a barrel assembly having a thumb ring attached to a plunger by a plurality of connecting rods, the plunger working like a piston inside a barrel having finger grips to cooperate with the thumb ring and a central locking rod to connect to a disposable shielded needle capsule, the capsule including a space for holding the supply of injection fluid and a movable piston at the top of that space for contact with the plunger, and a central tubular guide as a sheath for a hollow needle having a needle plug which is attachable to the locking rod and two spaced gaskets around the needle and positioned on each side of a passageway through the wall to be in alignment with a passageway through the tubular guide to allow the fluid to flow into the hollow of the needle.