If bleeding occurs when blowing your nose, the main consideration is that the blood vessels in the mucous membrane of the nasal cavity are ruptured when blowing your nose. Because the nasal cavity is very rich in blood vessels, blowing or rubbing the nose, or even sneezing, may cause the blood vessels in the nasal mucosa to rupture and bleed. However, if there is a large amount of nasal bleeding after blowing your nose, it is important to do an examination of the nasal passages to see if there are any new organisms in the nasal passages. If there are new organisms, you will also need to have a CT of the sinuses to see if it has caused any destruction of the sinus bone, and if there is destruction of the bone, sometimes pathology is needed to make a definitive diagnosis. Also if there is frequent bleeding from the nose and it is bilateral, it is important to consider doing routine blood tests and coagulation tests to see if there are any problems with the blood system.