Get the patient to bite on a piece of gauze, cotton wool, tissue paper or similar item for at least 20 minutes, making sure there is positive pressure on the extraction site (the other teeth will not usually meet when biting on the cotton wool).
Bleeding usually stops within 20 to 30 minutes following persistent application of pressure. Sometimes, a small amount of blood mixed with saliva in the mouth might give the impression that bleeding is more severe than it really is. Keep calm, and re-apply pressure for another 20 minutes if blood is still oozing after the first application
If the patient has a history of bleeding disorders (e.g. familial haemophilia) or is taking medication to increase blood clotting time (e.g. warfarin or a novel anticoagulant), it might be wise to be seen by a dentist to make sure everything is in order. You might need sutures or some medication to help stop the bleeding