Flat poop, or stool that looks thin and ribbon-like, can happen when your stool is softer than usual. This may be caused by changes in your diet, irritable bowel syndrome (IBS), or gastroenteritis, for example. Although rare, flat poop may also be a sign of a more serious condition, such as colorectal cancer.
With colorectal cancer, flat or ribbon-like stool may happen along with other symptoms, such as weight loss, blood in the stool, changes in bowel habits, abdominal pain, or anemia.
For this reason, it is important to see a healthcare provider, especially if the change in stool shape does not go away or is accompanied by other warning signs. They can identify the cause and recommend the most appropriate treatment.