Hi, Some people have nose bleed during withdrawal from nicotine. The exact cause is not known but is believed to be related to the positive changes that occur in the body when one quits smoking. Smoking increases the clotting tendency of blood and the consequent risk of stroke. When one quits, the body tries to go back to previous state and the sudden decrease of clotting factors in the blood can cause nose bleed. Also the blood pressure rises in withdrawal and this too contributes to nose bleed. Nose bleed should not be allowed to become an excuse for resuming smoking. I do not expect it to be life threatening in people who are otherwise healthy. Hope this helps your friend. Best wishes.