The duodenal bulb is a 2.5cm section of the upper duodenum near the pylorus, and is the most common site of duodenal ulcer. The duodenal bulb starts from the pylorus of the stomach, and is a 2.5cm section of the upper duodenum, with a thin wall, a smooth mucosal surface, and no or very few circular folds. The duodenal bulb is a favored site for duodenal ulcers, but clinically and statistically it has been shown that ulcers in this area do not turn into cancer. In addition, cancer in the posterior part of the duodenal bulb may infiltrate or compress the posterior common bile duct, causing the patient to develop obstructive jaundice. In case of duodenal lesions, please go to the hospital for appropriate treatment in order to control the disease in time and avoid complications.