Functional dyspepsia is often referred to as “indigestion”, which refers to a group of clinical syndromes with symptoms such as upper abdominal pain, upper abdominal distension, early satiety, belching (burping), loss of appetite, nausea, vomiting, etc., and the organic diseases causing these symptoms are excluded after examination. Symptoms may be persistent or recurrent, with a duration of more than one month or accumulated over three months in the past year. Functional dyspepsia is the most common type of functional gastrointestinal disorder in clinical practice. This means that there is no real disease in the body, but only a problem with digestive function (both motor and secretory functions). There are no characteristic clinical manifestations of functional dyspepsia, and symptoms can appear alone or several symptoms can appear at the same time. Several issues need to be understood: 1. Early satiety refers to a feeling of fullness soon after eating, resulting in a significant reduction in food intake. 2. Epigastric distension occurs mostly after meals, or is persistent and worsens after meals. 3. Early saturation of epigastric distension is often accompanied by belching. Nausea and vomiting are uncommon and often occur in patients with significantly delayed gastric emptying, and vomiting is mostly the stomach contents of the current meal. 4. Many patients are accompanied by insomnia, anxiety, depression, headache, poor concentration and other psychiatric symptoms. In some patients, these symptoms are related to the psychology of “cancer fear”. 5. The symptoms may change during the course of the disease, and the onset of the disease is slow, persistent or recurrent over the years, and many patients have triggering factors such as diet and mental illness.