IBS Pencil Stools

Medically Reviewed by: Nicole Anne Vergara, RD

Irritable bowel syndrome (IBS) is a common disorder that affects the large intestine and can cause a wide range of uncomfortable and embarrassing symptoms, such as cramping, abdominal pain, and changes in stool consistency.

One of the most common stool abnormalities associated with IBS is pencil thin stools. Pencil thin stools can be an indicator of an underlying health issue, so it's important to understand what they are, what causes them and how to treat them.


What are Narrow Stools?

Narrow stools, also known as ribbon stools, are a type of bowel movement that can indicate the presence of an underlying disorder. A narrow stool is defined as one that is less than 1 inch in width.

While the occasional narrow stool may not be cause for concern, if it persists or appears regularly, it could be a symptom of something more serious. 

Stool shape and size can provide valuable information to medical professionals about possible digestive issues, such as gastrointestinal obstruction or irritation due to an infection or inflammation.

In some cases, a narrow stool may also point to conditions like irritable bowel syndrome (IBS), Crohn’s disease, or celiac disease.

It can even indicate malabsorption syndromes caused by problems with digestion and absorption of nutrients from food.


What are the possible causes of thin stools?

There are currently three possible causes of thin stools, and of course, that includes IBS. Aside from IBS, here are other digestive issues that you have to take note of when you have narrow stools:



Inflammatory Bowel Disease (IBD) is a severe digestive illness that affects millions of people around the world.

It is characterized by abdominal pain, diarrhea, and weight loss, as well as other serious symptoms.

One of the most troublesome signs of IBD is narrow stools, which can make it difficult to pass waste through the body. 

Thin stools, also known as narrow stools or ribbon stools, are a common symptom of inflammatory bowel disease (IBD). Thin stools can occur in both Crohn's disease and ulcerative colitis.

These conditions cause inflammation in the gastrointestinal tract that can lead to changes in the shape of stool. Thin stools may be accompanied by other symptoms such as abdominal discomfort and cramping, diarrhea or constipation, fever, fatigue, and weight loss. 



IBS, or Irritable Bowel Syndrome, is a very common digestive disorder that affects many people around the world.

One of its many symptoms is the presence of pencil-thin stools, which can be both uncomfortable and alarming for individuals who have not been diagnosed with IBS. 

Pencil stools are usually about one centimeter in diameter and can range from light to dark in color. The length of these pencil stools can vary from person to person but they typically measure between two and four inches long.

These pencil-shaped stools are often caused by an imbalance in the muscles of the bowels, which results in a decreased ability to push stool out. This leads to thinning of the feces as it passes through the intestines.



Having narrow stools aren't always a sign of constipation, but it can be a reason if you are having constant constipation, and your stools look narrow, it can be a reason behind it.

Constipation is characterized with passing stools that are less than three times a week. An individual may have constipation especially if they lack fiber in their diet.


Colorectal Cancer

Thin stools can be an early indicator of colorectal cancer, also known as bowel cancer. This type of cancer begins in the cells lining the large intestine and is one of the most common types of cancers worldwide.

It is important to understand what may cause thin stools and when you should take further steps to investigate this symptom. 

The size and shape of your stool can give valuable information about your overall health. Generally, healthy stools are thick and well-formed, while thin stools indicate that something may not be right with either your diet or digestive system.

While having thin stools once in a while isn’t necessarily alarming, if it occurs consistently it might suggest there is an underlying problem such as colorectal cancer that needs to be addressed.


What Causes Thin Stools If You Have IBS?

If you have Irritable Bowel Syndrome (IBS), it's not uncommon to suffer from thin stools. This can be a symptom of a chronic condition that presents itself in many forms and affects the large intestine. Knowing what causes this symptom can help you better understand your IBS and manage its symptoms. 

Thin stools may be caused by changes in digestive motility, which is how quickly food travels through your gut. With IBS, there may be an increase or decrease in digestion speed due to an imbalance of hormones or other abnormalities in the digestive system.

In some cases, medications used to treat other conditions like depression and anxiety can also cause thin stools as a side effect.


When Should You Be Concerned If You Have Thin Stools?

Although thin stools seldom signal cancer, it would be advisable to consult a doctor if they have persisted for longer than two weeks. It's crucial to contact your doctor right away if changes in stool appearance are accompanied by symptoms of anemia, stomach pain, or cramping. These symptoms could be signals of cancer.


What Are Other Things You Should Look For?

If you have been noticing that you are getting frequent narrow stools, there are other signs and symptoms that you should look out for like the following:

  • Other changes in bowel movements
  • Other symptoms that accompany the narrow stools
  • Changes in your diet habits that may be the reason for narrow stools
  • Family history of colorectal cancer
  • New medications
  • How long has pencil stool been happening


Get Professional Help In Managing Your IBS

Nothing is better in managing your IBS symptoms than professionals who are always on the go to help you improve your overall quality of life even with IBS.

Casa De Sante's team of professional GI clinicians and dietitians offers in-depth and integrated nutritional and lifestyle therapies to help IBS and SIBO patients.


Book an appointment with us today!




Back to blog

You might want to check

1 of 12