Sit down and lean forward slightly while pinching your nostrils together using a thumb and index finger. Hold this position for at least five minutes, or until the bleeding has stopped. If the bleeding hasn’t stopped after 20 minutes or is the result of an injury to the face, seek medical attention. Nosebleeds can be treated by cauterizing the blood vessels or inserting packing into the nasal cavities. Sometimes, anticoagulants and anti-inflammatories can cause nosebleeds.