The symptoms of thinning stools and frequent gas evacuation are mainly considered to be the occurrence of space-occupying lesions in the rectum, such as rectal polyps, rectal fibroids, rectal cancer, etc. The main reason is that the human body needs to pass through the rectum in the process of defecation before passing out through the anus. Because the human body in the process of defecation, need to pass through the rectum and then through the anus out of the body. Occupational lesions in the rectum will lead to obstruction of excretion, thus causing the patient’s stool to become thin, difficult to defecate and other adverse symptoms. In addition, the excreta in the sigmoid colon, rectum and other parts of the stagnation, fermentation and decomposition will occur, resulting in the generation of gas. In addition to the stagnation of gas in the lower digestive tract, some of the gas will be expelled from the body through the way of venting, thus causing the patient to have frequent symptoms of venting. However, patients with incomplete anal atresia, hemorrhoids, and other digestive disorders can also experience these symptoms.