Flattened stools are caused by intestinal tuberculosis, intestinal polyps, intestinal tumors, hemorrhoids, and other diseases. Tuberculosis is caused by the invasion of the intestinal system by the tuberculosis bacterium. During an attack of tuberculosis, a swelling is formed in the intestinal system, which affects the formation of stool. However, some people have large intestinal polyps, which will affect the shape of stool. Some people will have flat and round stools, and when the polyps are stimulated by stool, they will also have blood in stool. Intestinal tumors are malignant diseases, and in the middle and late stages, the tumor will infiltrate the surrounding organs, thus causing the intestinal cavity to be relatively narrow, and the stool of these people will even look like a flat ribbon. Hemorrhoids mainly occur around the anus, and the disease leads to the presence of venous masses around the anus, which squeeze the feces when the stool passes through the anus, so the feces that comes out will also have a flat shape.