Symptoms of an upset stomach can be characterized by abdominal discomfort, a feeling of fullness, dull ache, nausea and vomiting. The stomach is an important digestive organ of the human body, located in the upper abdomen, below the diaphragm, connected to the esophagus at the upper end and the duodenum at the lower end. The stomach is capable of holding food and digesting it through the secretion of gastric juice, and also has the function of absorbing some nutrients, playing an important role in the digestion and absorption of food. If the stomach is diseased and causes stomach discomfort, it may be manifested as abdominal discomfort, fullness, dull pain, acid reflux, heartburn, belching, nausea, vomiting, loss of appetite, anorexia, vomiting of blood, black stools and other symptoms. The occurrence of the above symptoms should be taken seriously, and timely consultation should be made to identify the cause of the disease and follow the medical advice for further treatment or therapy.