Loose stools can be caused by either benign or malignant diseases. Among the common benign diseases are non-specific inflammation of the intestines, that is, the presence of inflammatory changes in the intestinal mucosa under colonoscopy, but the pathology does not reveal malignant tumors or other specific causes. There are also symptoms of loose stools as in the case of colonic polyps, which include inflammatory polyps, adenomatous polyps, and hyperplastic polyps, to name a few. In addition, inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis can also present with loose stools. Malignant diseases are commonly caused by tumors or lymphomas of the colon, etc. It is recommended that the patient should complete the colonoscopy plus pathological examination to make a clear diagnosis.