The pain of duodenal ulcer is located in the upper abdomen, mostly in the middle or slightly to the right of the epigastrium, and the exact location of the pain may vary depending on the location of the ulcer and the condition. The typical epigastric pain occurs in the fasting state, that is, when hunger occurs on an empty stomach before a meal, and the pain can be relieved after eating, as can alkaline foods such as soda crackers. Patients often experience pain between 10 and 11 am and between 4 and 5 pm. It also occurs at night on an empty stomach, especially in the second half of the night, and often wakes up with pain. The pain is mostly burning or dull and “rhythmic”, i.e., “pain-feed-relieved”. The pain can sometimes radiate to the corresponding area of the back. It may be accompanied by acid reflux, vomiting, and gastric distention. The typical patient’s epigastric pain tends to have a seasonal pattern, occurring in the fall, winter, or winter-spring, and it is also common for the pain to recur and resolve over multiple years, known as “cyclic” pain, which can resolve on its own. The pain can be relieved on its own. It can be aggravated by alcohol consumption or uncontrolled diet, and it can be aggravated by stress and exertion. When duodenal ulcers are severe, they can become perforated, resulting in sudden, severe all-abdominal pain that is unbearable and requires emergency medical attention. There are a few patients with duodenal ulcers that have no symptoms such as pain and are “silent ulcers”. These ulcers are more likely to develop complications. In general, the location of duodenal ulcer pain varies depending on the condition, so patients with a history of ulcers should go to the hospital for an examination if they have abdominal pain, no matter where it is, to identify the cause so as not to delay the condition.