Duodenal ulcers do not require biopsy because they are not cancerous, and the purpose of biopsy is to determine whether there is cancer. In addition, the wall of duodenum is very thin and it is likely to be perforated if biopsy or other treatment is done. Only a small percentage of gastric ulcers are cancerous, and the cancer rate is less than 1% when the gastric ulcer is at the edge of the ulcer. Biopsy is prohibited when the gastric ulcer is bleeding, because it will aggravate the bleeding. Whether it is duodenal ulcer or gastric ulcer, both need to be given regular treatment under the guidance of a gastroenterologist, especially duodenal ulcer patients are prone to complications, such as bleeding, perforation, obstruction, etc., so they must be treated with regular medication in cooperation with the doctor.