Nasal polyp bleeding mainly has three causes. One reason is that the nasal polyp damages the structure of the nose. Since nasal polyps are a space-occupying lesion, they gradually enlarge, compress the nasal structures, and damage the mucosa and blood vessels of the nose, which can lead to nasal bleeding. The second reason is that the nasal polyp itself may be a bleeding necrotic nasal polyp. This type of bleeding necrotic nasal polyp is very prone to bleeding, and even minor injuries or damage can lead to bleeding. The third reason is that bleeding necrotic nasal polyps might be a manifestation of the disease. As the nasal polyp enlarges, if such an enlarged polyp becomes lodged in a sinus opening or in the nasal cavity, it can lead to ischemic necrosis, which after occurring, can cause bleeding. In summary, these are the three main cases.