Abstract: A safety syringe for preventing "needle stick" injury and/or reuse of the syringe includes a body (2), a plunger (4) mounted within the body, connection means (24) for connecting the plunger (4) to a needle holder (6) whereby subsequent retraction of the plunger (4) withdraws the needle holder (6) and the needle with a shielded position within the body (2) effected by a vacuum chamber (18) defined between the plunger (4) and the syringe body (2), vacuum being created within the chamber (18) by movement of the plunger (4) during the injection stroke and serving to withdraw the plunger (4), the needle holder (6) and needle after injection pressure is removed. The syringe may be provided with braking means (20) to control the rate of withdrawal of the needle and/or to prevent withdrawal until the injection stroke of the plunger (4) has been completed.