The reasons for feeling hard stomach are as follows: 1. It is related to prolonged flatulence, indigestion and gastrointestinal dysfunction. If it is accompanied by heartburn, acid reflux, stomach pain and other uncomfortable symptoms, it may suffer from gastritis or gastric ulcer, and gastroscopy should be performed to clarify the cause. 2. Leathery stomach, which is a serious type of gastric cancer, because the tumor invades into the muscular layer and plasma membrane layer, thickening and stiffening the whole layer of the stomach wall, it can also show a hard stomach, even touching as if a lump, and abdominal CT and upper gastrointestinal barium imaging other than gastroscopy are needed to assist in clarifying diagnosis. Therefore, when patients develop GI symptoms, they must undergo relevant examinations to clarify the cause and be given medication and lifestyle adjustments to promote recovery.