Very thin stools may be caused by indigestion, colon cancer and intestinal diseases. 1. Dyspepsia: it may cause intestinal dysfunction, resulting in localized congestion and edema of intestinal mucosa, which in turn leads to thin stools. 2. Colon cancer: it may cause partial obstruction of intestinal tract, resulting in difficulty in defecation, leading to thinning of stools or even bloody stools. 3. Intestinal diseases: intestinal polyps or malignant tumors may cause partial narrowing of the intestine, which may lead to thinning of stools; ulcerative proctitis or ulcerative colitis may cause recurrent ulcers, which may lead to partial narrowing of the intestine, causing thinning of stools. The thinning of stools may also be caused by other reasons, it is recommended to consult a doctor in time, under the guidance of the doctor to carry out targeted treatment.