A self-releasing tourniquet apparatus comprises an elongate strap and a housing. The strap has a first end and a second end and a plurality of holes arranged at substantially regular intervals along its length. The first end of the strap is connectable to the housing. The housing includes a projecting element sized to be received in one of the plurality of holes on the strap. The housing includes means for moving the projecting element from a first position to a second position after a predetermined period of time, and also includes timer means for measuring the predetermined period of time. In use, the strap is tensioned around a patient's limb when the projecting element is in the first position, and tension is released when the projecting element is in the second position.