What Causes Narrow Stools And How To Treat It?

Narrow stools
Medically reviewed by Dr. Mandy Liedeman


The term “narrow stool” describes feces smaller in diameter than usual and identifies several health problems. The cause of narrow stools may be constipation, irritable bowel syndrome (IBS), colon cancer, or other gastrointestinal conditions. In addition, your healthcare provider can help identify the problem and provide effective remedies. See a doctor right away if your stools are thin.

What is Narrow Stool?

The narrow stool is pencil-thin, ribbon poop, or narrow-shaped stringy poop. In some cases, it’s both thin and flat stool. It could be rigid or fluid. Its estimated diameter is somewhere between one to two inches.

You can experience narrow stool in combination with additional gastrointestinal symptoms like nausea and cramping in the stomach.

To know what your springy narrow poop is trying to indicate, let’s look at the causes in detail.

Causes of Narrow Stool

Causes of Narrow Stool can be both dependent and independent. Independent reasons, like your dietary intake, are in your control, but independent causes are out of your reach! Because it’s some infection or disease that makes your poop shape unusual.

Here are some most common causes of narrow stool.

Low Fiber Diet

Diet is the most influencing factor that can help maintain healthy bowel movements and frequency. When it comes to a thin narrow poop, it is most likely to be experienced by obstructions that develop in the colon due to chronic constipation. As a result, the stool size may be less, making it seem narrow and stringy. Constipation occurs more often if you eat a diet low in fiber.

As this cause depends on your dietary intake, you can easily manage it by adding insoluble fiber.

Intestinal Infection 

Intestinal infection is an independent cause of where the body may experience altered bowel movements and thin stools. Infection can be mainly in the colon, for example, gastroenteritis. Narrow stools may result from a constricted stoma channel caused by inflammation of the intestines.

Inflammatory bowel syndrome (IBS)

Inflammatory Bowel Syndrome, a condition of the large intestine, may lead to abnormal bowel movements and frequency. Moreover, it causes intestine swelling, ultimately altering the stool shape and turning it into a bit of pencil poop. 

Gastrointestinal parasite infections

Parasites can be the silent enemy that is causing a disturbance. Gastrointestinal Parasites, also known as roundworms such as little worms, might cause thin and narrow stool or diarrhea. They can survive in your gut after living in the soil and getting into your diet. 

 Other Causes

The following also includes the causes of narrow stools:

  • Anorectal stricture is a dilated or constricted colon, Obstructing the rectum and anus.
  • A tiny growth or polyp in the colon, known as fecal impaction, or a mass of hard stools trapped there.
  • Colon inflammation carried on by Crohn’s disease or ulcerative colitis 
  • Abdominal Hernias
Narrow stools may be a sign of an underlying condition. You should seek professional support.

Medical Conditions Associated with Narrow Stool

Following are the common coexisting or related medical conditions with narrow stools. 


These, often known as piles, are most likely veins with swelling similar to varicose veins in the lower rectum and anus. Also, hemorrhoids can form under the skin around the anus (external hemorrhoids) or inside the rectum (internal hemorrhoids)

Narrow stools may result from hemorrhoids. Numerous factors might lead to hemorrhoids, including:

  • Straining when having bowel movements
  • Spend a lot of time on the toilet
  • Persistent diarrhea or constipation
  • Consuming low-fiber food
  • Lifting heavy objects repeatedly
  • Being overweight or obese
  • Pregnancy 

Usually, increased abdominal pressure causes hemorrhoids to form.


Diverticula are small, sharp-edged pouches that can develop in the lining of your digestive tract. They are usually present in the lower part of the large intestine (colon). When diverticulosis significantly worsens, the lower colon may become highly fixed, twisted, and restricted. It can lead to constipation, thin poop, and the sporadic start of diarrhea.

Fecal Obstruction

Fecal impaction, similar to constipation, occurs when a  bulk of dry stool is stuck or lodged in the rectum and blocks the path of stool, making evacuation difficult. Thin feces pass through the blockage.

Colorectal Cancer

Narrow stools could indicate a cancerous gut tumor around the anus. For those concerned about narrow stools as an indicator of potential colon issues, it’s important to consider early diagnosis from healthcare providers. Consultation with healthcare professionals for a thorough colon cancer screening can provide peace of mind and crucial preventative measures.

Anal Cancer

Skinny stool caused by HPV (human papillomavirus)may result from this rare form of cancer. Feeling bloated and rectal bleeding are common symptoms.

Crohn’s Disease and Ulcerative Colitis

Changes in the stool can result from Crohn’s disease. The feces’ frequency, consistency, and appearance may differ from regular due to the inflammation (swelling and redness) and ulcers carried on by Crohn’s disease in the small or large intestine.

Twisted bowel (Volvulus)

“Volvulus” means when an intestine loop bends around itself and obstructs the gut. In several disorders, Volvulus may transmit diseases like Hirschsprung disease. 

Read More: White Specks In Your Poop: Causes, Treatment and Complications

Risk Factors of Narrow Stools

  • Age
  • A family history of the condition
  • Personal history of inflammatory bowel disease
  • A diet rich in red or processed meat
  • A sedentary lifestyle is a risk factor for colorectal cancer
  • A history of abdominal surgery, particular drugs, and specific medical diseases like Crohn’s Disease are risk factors for intestinal blockage.
Narrow stools may indicate a gastric problem or IBS. Get professional advice now!


Suppose you frequently see changes in the appearance of the stool, or it may be narrower than usual. In that case, your doctor can refer you to a rectal or colon specialist who can suggest various tests to diagnose the disease. Doctors recommend several methods.

Fecal Occult Test

A fecal occult test (FOBT) is to find hidden blood in stool samples. Additionally, this test checks for colorectal cancer and other gastrointestinal conditions that may result in gastrointestinal bleeding. Moreover, the FOBT test takes a tiny feces sample and checks in a lab to identify whether blood is present. The guaiac-based FOBT (gFOBT) and the fecal immunochemical test are the two types of FOBT assays (FIT). To detect the presence of blood in the stool, the gFOBT test uses a chemical called guaiac, which turns blue with the sample.

Stool Sample Test

A doctor can also recommend doing a stool sample examination for infections. Using a stool culture, the doctor can check whether the intestines have bacterial contamination.

Little stool samples are collected by a technician in sterile plastic dishes with nutrients that promote the growth of particular bacteria. Growth will occur only if the targeted bacteria are already in the stool sample.

Blood tests to detect infection

The process of a blood test is simple and familiar. Lab attendants examine particular biomarkers that analyze the blood changed composition. When inflammatory bowel disease is present, a blood test will show an increased white blood cell count, which could indicate inflammation.

Imaging tests

The following tests are essential to get the correct diagnosis 

  • CT Scan
  • Ultrasounds
  • X-ray imaging of your abdomen and pelvis

The doctor may occasionally use a CT scan or X-ray to obtain a better image of the colon and rectum. These examinations can reveal further information regarding the internal structure of the organs and other abnormalities.

Endoscopy or colonoscopy

Medical techniques like endoscopy and colonoscopy can help identify the root cause of thin stools. In these procedures, a doctor may insert a long, flexible tube with a camera at one end into the colon and rectum to check their linings.

When a patient experiences thin stools, the doctor may detect a constriction or obstruction in the colon or rectum. In addition, you can use endoscopy or colonoscopy to find the position and size of any blockage.

The doctor may do a biopsy, which comprises collecting a microscopic tissue sample for analysis if an obstruction is found. It can help determine whether a tumor, scar tissue, or inflammation is the cause of the block.

Flexible Sigmoidoscopy 

Flexible sigmoidoscopy is another medical diagnostic procedure to find the cause of narrow stools. Like a colonoscopy, this operation focuses on inspecting only the rectum and the bottom part of the colon, called the sigmoid colon.

During a flexible sigmoidoscopy, a doctor inserts a flexible tube with a camera on its end into the rectum and sigmoid colon. Also, they are making it possible for the doctor to identify any irregularities, including inflammation, polyps, or tumors, on the lining of these organs.

Getting the right diagnosis for symptoms like narrow stools is important. You should discuss this with a doctor.

Narrow Stool Treatment

The following treatment options are most commonly applied during clinical practices.


If enema and manual removal are failed, a doctor may advise laxatives. In addition, they increase the amount of water the colon produces, softening the impacted stool and facilitating removal.

Stool Softeners

These are prescription drugs that ease constipation and improve bowel movements. Stool softeners make stools easier to pass by increasing the amount of water and fat in the stool. Furthermore, stool softeners, which produce softer, easier-to-pass feces, can help reduce symptoms of narrow stool disease.

Water Irrigation

A short tube irrigating the colon is pushed into the rectum. A machine that emits water through a tube is connected to the hose. After the irrigation, your doctor will massage your abdomen to help another line remove the waste from your rectum.

Increasing Water Consumption

Drinking more water is a quick and efficient way to ease the symptoms of a narrow bowel movement. Furthermore, water is necessary to keep a soft bowel movement and avoid constipation, which can result in pencil poop and difficulty in releasing.

Fiber-rich diet

You can promote regular bowel movements and avoid constipation by increasing your diet with high-fiber meals, including fruits, vegetables, and whole grains. Also, it is essential for narrow stool disease because constipation worsens symptoms.


Surgery might be necessary in some cases of narrow stool illness, mainly if a physical obstruction or structural issues are responsible for the symptoms.

The following surgical methods could be used to treat narrow stool disease.

Bowel resection

In this procedure, a segment of the bowel that has been obstructed or narrowed is removed. Reconnecting the remaining intestinal ends restores normal bowel function.


This treatment includes making lengthwise incisions and then suturing the incisions to increase the diameter of the gut to enlarge a narrowed segment of the colon.

Colostomy or ileostomy

In some circumstances, a temporary or permanent opening (stoma) may be made in the abdomen to allow stool to flow through a constricted or blocked part of the colon.

Anticholinergic medicines

It is a neurotransmitter that functions in various biological activities, including regulating bowel movements. Anticholinergic medications are a type of medicine that suppresses this neurotransmitter’s action. These drugs may help treat symptoms of thin stools.

Anticholinergic drugs treat constipation by relaxing the smooth muscles of the intestines, which might promote more frequent bowel movements.


Painkillers are not preferable for treating narrow stools since they can aggravate the symptoms of constipation and narrow stools. Also, opioids and other painkillers can slow the passage of stools through the digestive tract and lead to constipation, making feces more challenging to pass. In some circumstances, non-opioid painkillers, physical therapy, or other non-pharmacological treatments may reduce pain.


Specific antidepressants can help treat narrow stool disease. A particular class of antidepressants, tricyclic antidepressants (TCAs), can help treat narrow stools. Also, TCAs prevent the brain from absorbing certain neurotransmitters, which can help in mood regulation and anxiety reduction. Moreover, these drugs might stimulate regular bowel motions and ease constipation.

Radiation and Chemotherapy

The colorectal and anal cancer treatment plan depends on the cancer’s stage, the tumor’s location, and other circumstances like the patient’s age and general health. Additionally, radiation therapy, chemotherapy, and surgery are options in combination with treatment.

Read More: Poop Looks Like Coffee Grounds – Causes and Treatments

When to Consult a Doctor

If your bowel motions change or you have prolonged thin stools, consult your doctor; it can signify a more serious medical problem that needs diagnosis and treatment. Call your doctor immediately if your bowel changes are accompanied by severe stomach discomfort or rectal bleeding.

A narrow stool may indicate a serious illness; you should not ignore it. Talk to an online doctor.

FAQS about Narrow Stools Answered by Your Doctor Online

What Medications Can Cause Thin Stools?

NSAIDs, often called nonsteroidal anti-inflammatory drugs, include aspirin, ibuprofen, and naproxen. These medications may disrupt the digestive tract’s lining and cause bleeding, which may cause thin stools.
Heparin and Warfarin can also increase the risk of gastrointestinal bleeding, resulting in narrow stools. Moreover, antibiotics like penicillin or clindamycin may alter the average bacterial balance in the gut, changing bowel patterns and causing thin stools by taking supplementing iron. However, narrow stools may arise from constipation brought on by iron supplementation. Antacids with aluminum hydroxide may result in constipation, which might cause pencil poop.

What is a normal stool look like?

The color of normal feces ranges from tan to espresso and is always brown.

What does a healthy bowel movement look like?

Although the appearance of a good bowel movement might vary, it should typically be easy to pass and smooth.

Can stress and anxiety cause thin stools?

According to research, high-stress levels can disturb the digestive system, resulting in thin stools.

Can polyps cause narrow stools?

Polyps could be a condition that could impact how stool passes through or leaves the colon, causing narrow stool.

What does green poop mean?

Green poop is usually due to consuming green meals, such as leafy green vegetables, taking iron supplements, and having insufficient bile in your feces.

Why is there thin stool and gas?

IBS patients suffer from diarrhea, feces that change in texture and shape, gas, bloating, and constipation.

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