Pencil-thin poop could be a sign that there’s a narrowing in your colon or a blockage, explained gastroenterologist Dr. Elizabeth Rajan (via Mayo Clinic).
Your colon can narrow for a few different reasons, like diverticular disease, inflammatory bowel disease (IBD), ischemic colitis, radiation-induced colitis, anastomotic strictures, hernias, bacterial infections, and reduced blood flow to the area, also known as ischemia. Sometimes, it can happen because of rectal or colon cancer. With colon cancer, a tumor could be taking up space in your colon and restricting the passage of stool, resulting in narrow poop.
“Irritable bowel syndrome (IBS) also may cause changes in the size of your stools. IBS can cause stools to be smaller, larger or narrower than usual. It also causes changes in the consistency of stools,” added Dr. Rajan. However, health conditions that cause super-thin poop won’t only cause stool-related symptoms. There are other warning signs to watch out for as well.