Direct Pressure

First and foremost, if the knife is still embedded in the body, DO NOT REMOVE IT!

If someone is bleeding, apply direct pressure to the wound site. Preferably you will have gloves on, as not only do they provide a good barrier for infection, but they also act as a good seal. Even if the knife is still in place, apply pressure around the knife onto the wound. Direct Pressure helps the blood to clot, therefore helping to cease the blood flow. You want to keep as much blood in the body as possible, as this will increase the chances of survival and decreases the chances of any long-term problems forming. Applying firm, direct pressure on the wound may hurt the person, but explain that you are helping the bleeding to stop. Depending on how big the cut is, and where on the body the patient has been cut, they may be able to apply pressure themselves. Keep an eye on them however as they may pass out or become tired. Should the blood flow cease, then you can start to think about applying a dressing.