What causes narrow stools? Should I be concerned?

Narrow stools that happen now and then probably are harmless. But in some cases, narrow stools — especially if pencil thin — may be a sign that the colon is narrowing or has a blockage. And that could be due to colon cancer.

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.

Check with a healthcare professional if you notice any changes in the appearance of your stool that last longer than 1 to 2 weeks. Get medical help right away if your bowel changes happen with rectal bleeding or severe belly pain.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

We use the data you provide to deliver you the content you requested. To provide you with the most relevant and helpful information, we may combine your email and website data with other information we have about you. If you are a Mayo Clinic patient, we will only use your protected health information as outlined in our Notice of Privacy Practices. You may opt out of email communications at any time by clicking on the unsubscribe link in the email.

Jan. 11, 2024 See more Expert Answers

See also

  1. Hilar cholangiocarcinoma
  2. Mucus in stool: A concern?
  3. Stool color: When to worry
  4. Undigested food in stool
  5. White stool: Should I be concerned?