The onset of duodenitis is easily confused with other gastrointestinal diseases from its symptoms alone. Most patients can show varying degrees of epigastric pain, which can be characterized by pain after hunger, pain at night, and relief after eating, but some patients also show increased pain after a full meal. In addition, it may also be accompanied by the following symptoms: 1. epigastric pain: burning-like or hunger-like pain in the epigastrium or the glabella, etc., which is more severe when fasting and can be relieved after eating and can clearly point out the pain area; 2. loss of appetite: patients with epigastric fullness and fading hunger can have different degrees of reduced food intake, and in severe cases, they may even become anorexic and lose weight; 3. acid reflux: reflux of gastric juice into the oral cavity. It often occurs when eating, exerting, changing position, especially when lying down or bending over, and may be accompanied by the overflow of bile and pancreatic juice; 4. belching: commonly known as belching, the act of gas in the stomach retrograde to the throat to make a loud sound; 5. erratic: an act of frequent throat sounds due to spasmodic contraction of the diaphragm; 6. upper gastrointestinal bleeding: tarry black stools or vomiting of coffee-colored liquid may occur. Tarry black stool is a stool with a shiny surface due to the presence of mucus. When the above symptoms appear, especially when accompanied by gastrointestinal bleeding, patients should go to the hospital for a clear diagnosis and timely treatment. Because duodenitis is often accompanied by other gastrointestinal diseases, such as chronic gastritis, hepatitis, as well as cirrhosis, biliary tract diseases or chronic pancreatitis, and may also be secondary to gastrointestinal diseases, such as Crohn’s disease, intestinal tuberculosis, peptic ulcer, etc., it is more important to treat the primary and secondary diseases in a timely manner to avoid adverse consequences.