Stage A2 gastric ulcer in the gastric sinus is the endoscopic staging of ulcers. Specifically, the ulcer disease occurs in the gastric sinus and is in the active stage. At this time of the year, thick moss and reduced peripheral mucosal elevation are seen at the base of the ulcer in the gastric sinus and there is no active bleeding. A small amount of regenerating epithelium is shown which is categorized as stage A2 gastric ulcer. Endoscopically, gastric ulcers can be categorized into active stage A, healing stage H, and scarring stage S. The gastric ulcers can be classified into two stages. Each cycle is then divided into two stages, denoted as stage A1, A2, H1, H2, S1, and S2. With effective treatment and good disease control, disease progression usually progresses from the active phase to the healing phase and then to the scarring phase. Treatment of stage A2 gastric sinus ulcer is mainly pharmacologic and endoscopic. Commonly used medications include omeprazole, ranitidine, and magnesium aluminum carbonate, and endoscopic hemostasis is usually required if complications such as severe bleeding occur. If the patient is diagnosed with gastric sinus ulcer stage A2, please follow the doctor’s instructions for standardized diagnosis and treatment.