Common causes of hard stomach in men include physiological factors, constipation, intestinal flatulence, intestinal obstruction, abdominal tumors, peritonitis and liver diseases. 1. Physiological factors: physical exercise to form abdominal muscles can show a hard stomach. Eating high-fat, high-calorie food, insufficient activity, excessive fat accumulation, abdominal obesity, showing a large and hard stomach. 2. Constipation: constipation caused by indigestion, intestinal contents can not be discharged in a timely manner in the stagnant intestines, resulting in abdominal hardness. 3. Intestinal flatulence: the peristalsis of intestines is slowed down, and the gas cannot be discharged in the intestines, resulting in a hard and full abdomen, which can be relieved after exhausting the gas or having a bowel movement. 4. Intestinal obstruction: when intestinal obstruction occurs, feces and other intestinal contents accumulate in the intestines and cannot be discharged in time and accumulate in the abdomen, resulting in a hard stomach, accompanied by stopping defecation and exhaustion, abdominal pain and other phenomena, which may cause severe vomiting. 5. Abdominal tumor: if the patient has tumors in the abdomen, such as liver cancer, pancreatic cancer, etc., the stomach may become big and hard when the tumor grows rapidly. 6. Peritonitis: acute appendicitis with periappendiceal abscess, perforated appendix and acute peritonitis caused by gastric perforation, etc., the stomach will be large and hard, and there are obvious signs of peritoneal irritation, such as pressure pain, rebound pain and slab-like abdomen. 7. Liver disease: there is a history of chronic hepatitis, cirrhosis, may produce abdominal fluid that is ascites, when the amount of ascites is more, the abdominal wall tension increases, the abdomen will be hard. In summary, men with symptoms of a hard stomach, to rule out physiological factors, should be timely consultation, under the guidance of the doctor to choose the appropriate treatment program, so as not to delay the condition.