The left side of the stomach is always jumping and is related to constipation, irritable bowel syndrome, proctitis, rectal tumors and other factors. After the formation of feces, it is mainly stored in the lower left abdomen of the body, that is, in the sigmoid colon and rectum. When constipation is present, toxic substances in the stool can cause irritation to the intestinal mucosa, and some people may feel a throbbing sensation in the intestinal system when the intestine is irritated, and may have difficulty in defecating. Irritable bowel syndrome has nothing to do with organic factors of the digestive system. Many people have episodes of the disease due to food allergies or bad emotions, and spasms and contractions of the intestines occur during the episodes of the disease. When the site of intestinal spasm and contraction is located in the left abdomen, it will feel like the left side of the stomach is throbbing. The lower left abdomen of the stomach belongs to the rectum, and when there is inflammation or tumor in the rectum, it will not only affect the function of the rectum, but also cause the rectum to be overly sensitive, resulting in the feeling that the left side of the stomach is always throbbing.