Are Hemorrhoids To Blame For Thin Stools?

Despite the associated discomfort, doctors recommend checking your stool's appearance once in a while. Often, such awareness can help you address severe health conditions as early as possible.

Stools can have different characteristics — narrow, watery, hard, lumpy, etc. What does it mean if your stool is thin? Can hemorrhoids cause thin stools?

Addressing your hemorrhoid concerns early on can avoid further harm and health concerns such as narrow stool. Besides affecting your bowel movements, hemorrhoids can cause pencil-thin stool. Check out this article on how you can experience thin stools due to hemorrhoids. 

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We make it easy for you to participate in a clinical trial for Hemorrhoids, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

Causes of narrow stool

Narrow-diameter stools mostly occur due to a change in bowel movements. Bowel movement changes can be harmless, resulting from temporary infections or low-fiber diets. Pencil-thin stool can also indicate other underlying conditions, such as colorectal cancer, hemorrhoids, irritable bowel syndrome (IBS), etc. Common causes of narrow stools include:


Constipation can be the main cause of thin stool. You can avoid constipation by increasing your fiber intake and physical activity. 

Colorectal cancer

Though not common, narrow stools could also point to colorectal cancer. However, this cancer will most likely be accompanied by other symptoms. Speak with your doctor for further testing.

Anal cancer

This rare form of cancer can cause thin stools caused by HPV (human papillomavirus). Common symptoms include feeling bloated and bleeding from the rectum. 

Fecal impaction

Though similar to constipation, fecal impaction is when a lump of dry stool gets stuck in the rectum and blocks the ability of stool to pass normally. The blockage then causes narrow stools to pass. 

Can hemorrhoids cause thin stools?

Yes, hemorrhoids can cause narrow stools. Hemorrhoids can develop from several causes, including:

  • Strain during bowel movements

  • Sitting for prolonged periods on the toilet

  • Constipation or chronic diarrhea

  • Eating low-fiber diets

  • Regular heavy-weight lifting

  • Being obese

  • Being pregnant

In most cases, hemorrhoids can result from increased pressure in the abdomen. 

Can hemorrhoids cause pencil-thin stools?

Hemorrhoids exist in different categories, including internal and external hemorrhoids. Understanding the symptoms of each can help you seek effective solutions. 

External hemorrhoids are generally characterized by constant itching or irritation around the anus. Other symptoms may include swelling or bleeding. 

On the other hand, as the name suggests, internal hemorrhoids develop within the rectum. It is almost impossible to see or feel internal hemorrhoids. Surprisingly, internal hemorrhoids don't cause as much discomfort as external hemorrhoids.

However, if you strain when having bowel movements, you may experience painless bleeding. Other signs include blood-stained tissue paper after wiping. 

It is also possible to have thrombosed hemorrhoids. These are when clots form inside hemorrhoids, resulting in swelling, inflammation, severe pain, and a hard lump lodged next to the anus. 

Hemorrhoids — whether internal, external or thrombosed — can affect the shape of your stool. However, this will depend on the severity of the hemorrhoids. Not surprisingly, it is possible to have hemorrhoids without any changes to the shape and size of your stool. 

What is the normal stool size?

It is easy to assume that thin stool directly points to hemorrhoids. While there is some truth to this, not every instance of unevenly sized stool automatically points to hemorrhoids. 

There is no normal stool size since people are different, meaning bowel movements also differ.  Do you suspect narrow stools from hemorrhoids? Instead of checking for "normal," look for a change. If you've had consistent stool sizes over time but notice a drastic change, this could point to an underlying issue — possibly hemorrhoids. 

Alternative possible explanations for narrow stools

Visit your doctor immediately if you notice pencil-thin stools. Depending on the symptoms, the most common diagnosis would be hemorrhoids. Unfortunately, hemorrhoids may not always be the cause of thin stools.

The doctor will conduct several tests to help determine the cause of thin stools and related symptoms. These tests will depend on the symptoms present. They include:

  • Sigmoidoscopy if there is a need to examine the large intestine or lower part of the colon

  • Colonoscopy to examine the colon

  • Digital rectal examination to examine the rectum.

  • Blood tests to check for anemia that can point to internal bleeding

Based on the outcome of these tests, possible alternative explanations for pencil-thin stools may be:

  1. Obstruction/narrowing of the colon due to colon cancer

  2. Irritable bowel symptom, which affects stool size and consistency 

What medications can cause thin stools?

Thin stools can result from medications that slow down the intestines' movements. They can lead to constipation and fecal impaction, resulting in thin stools. Medications that can cause such effects to include:

  • Antidiarrheal medications are taken too often

  • Anticholinergics, such as oxybutynin

  • Opioid pain medications, such as hydrocodone and morphine. 

How to treat thin stools

There are no dedicated treatment solutions for thin stools. However, treating the underlying conditions can help return things to normal. To treat constipation, increase your fiber intake and stay hydrated. 

Colorectal cancer treatment can vary depending on how advanced the cancer is. Doctors can recommend surgery, followed by radiation or chemotherapy, or both. 

In the case of fecal impaction, treatment is manual, where your healthcare provider will use a gloved, well-lubricated hand to insert one or two fingers in the rectum and break down the stool for easy removal. They may also use interventions such as suppositories or enemas. 

When to see a doctor about a narrow stool

If you notice narrow stools accompanied by pain in the anus, you may have hemorrhoids and should seek medical attention. To avoid making assumptions, check with your doctor if you notice any changes in your stool’s appearance, such as pencil-thin stool.

Visit your doctor immediately if the bowel changes are accompanied by severe abdominal pain and rectal bleeding. 

The lowdown

Hemorrhoids can cause pencil-thin stools. While this is a common diagnosis, you should see your doctor if the problem persists and is accompanied by symptoms such as rectal bleeding, pain, and discomfort. Ensure you eat a fiber-rich diet, hydrate well, and exercise regularly, as this will help prevent the development of hemorrhoids.

More importantly, seek immediate medical attention in case of changes in your bowel movement appearance or blood in the stool.

Have you considered clinical trials for Hemorrhoids?

We make it easy for you to participate in a clinical trial for Hemorrhoids, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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