Ribbon-like stools are caused by irritable bowel syndrome, colon cancer and benign issues, such as a change in diet, according to About.com and Dr. Mercola. About.com notes that isolated instances of ribbon-like stools normally don't signal a health problem, but chronic ribbon-like stools need evaluation. In evaluating ribbon-like stools as a possible symptom of disease, a doctor generally needs to know what is a normal stool for the individual.
In the case of colon cancer, the stool becomes ribbon-like because the tumor that's growing in the colon creates an obstruction that only thin stools can bypass, according to Dr. Mercola. Non-cancerous ribbon-like stools can be treated by increasing fiber intake, taking probiotics, reducing stress and avoiding artificial sweeteners.
A healthy stool is normally sausage shaped, smooth and soft, according to Dr. Mercola. Healthy stool contains 75 percent water and 25 percent fiber, bacteria, cells and mucus. The human body normally takes 18 to 72 hours to convert food into stool and pass it. When the time for passing stool is less than normal, diarrhea results because the body has not had sufficient time to absorb the stool's water. If the time to pass stool is longer than normal, the body absorbs too much of the stool's water, resulting in dry stools and constipation.