Abstract: A protective apparatus, for a hypodermic syringe having a barrel and a needle has an elongated sleeve slidingly engaging the barrel of the syringe. There is a L-shaped locking and guide groove on the barrel of the syringe. A locking and guide tab on an inside wall of the sleeve slidingly engages and traverses the locking and guide groove. A locking slot, in the locking and guide groove, receives and locks the locking and guide tab in place to discourage further use of the syringe by limiting further longitudinal movement of the sleeve along the barrel of the syringe. There is a first seal, in one end of the sleeve which abuts the inside wall of the sleeve and abuts an outside wall of the barrel of the syringe, to seal the one end against the barrel of the syringe. A second seal, in another end of the sleeve, seals around an outer wall of the needle when the sleeve is in a retracted position on the barrel of the syringe.