Narrow or Thinning Stool
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Try one of these related symptoms.
Thin stools
Long and thin poop
Stringy poop
Pencil thin stools
Poo became thin
Narrow stools
About the Symptom
Decrease in poop size or shape causing your poop to look narrow or pencil-like.
When to See a Doctor
Seek professional care if you experience any of the following symptoms
- Thin narrow stool
Possible Causes
Generally, Narrow or thinning stool can be related to:
- Colon Cancer
Cancer of the large intestine which is the final part of the digestive tumors. It often grows from non-cancerous polyps in the intestine. Both polyps and colon cancers can be found during colonoscopy (camera test of colon). Symptoms can include blood in stool, diarrhea or constipation or both, or abdominal pain but many times there are no symptoms and the cancer is found on colonoscopy. It can be easily treated in early stages, so the general population is encouraged to get screened with colonoscopy and sometimes stool tests. Risk factors include a family history of colon cancer or polyps, or a personal history of abnormal polyps, low-fiber high-fat diets, some inflammatory bowel diseases, diabetes, obesity, and lack of exercise.
- Colonic Polyp
Colonic polyps are benign growths that appear on the inner lining of your large intestine. Some have a chance of becoming malignant or cancerous over time.
Related Serious Diseases
Sometimes, Narrow or thinning stool may be related to these serious diseases:
- Diverticular Bleeding
The walls of the intestines sometimes have small pouches called diverticula. Risk factors include chronic constipation, aging, and obesity.
Doctor's Diagnostic Questions
Your doctor may ask these questions to check for this symptom:
- Is your stool thin and narrow like a pencil?
- Are your stools greasy and smelly?
- Is there mucus in your stools?
- Have you noticed any changes in the shape of your stool?
- How often do you experience an abnormal stool shape?
Reviewed By:
Samantha Nazareth, MD (Gastroenterology)
Board-certified gastroenterologist. Experience managing gastrointestinal conditions (GERD, IBS, ulcerative colitis, Crohn’s, celiac disease, NASH) within healthcare organizations (three ambulatory surgical centers, single-specialty practice, multi-specialty practice and solo practice).
Aiko Yoshioka, MD (Gastroenterology)
Dr. Yoshioka graduated from the Niigata University School of Medicine. He worked as a gastroenterologist at Saiseikai Niigata Hospital and Niigata University Medical & Dental Hospital before serving as the Deputy Chief of Gastroenterology at Tsubame Rosai Hospital and Nagaoka Red Cross Hospital. Dr. Yoshioka joined Saitama Saiseikai Kawaguchi General Hospital as Chief of Gastroenterology in April 2018.
Content updated on Feb 6, 2025
Following the Medical Content Editorial Policy
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- Smaller caliber stool
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FAQs
Q.
Can hemorrhoids lead to the development of thin stools?
A.
Hemorrhoids are not known to cause thin stools. Thin stools are not typically linked to hemorrhoids.
References:
Johannsson HO, Graf W, & Påhlman L. (2005). Bowel habits in hemorrhoid patients and normal subjects. The American journal of gastroenterology, 15667500.
https://pubmed.ncbi.nlm.nih.gov/15667500/
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Brazell HD, Patel M, O'Sullivan DM, Mellen C, & LaSala CA. (2014). The impact of pessary use on bowel symptoms: one-year .... Female pelvic medicine & reconstructive surgery, 24566213.
Q.
Does having thin stools always indicate cancer?
A.
Thin stools do not always mean cancer. They can be caused by other factors, like changes in bowel function.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
van Dam JH, Gosselink MJ, Drogendijk AC, Hop WC, & Schouten WR. (1997). Changes in bowel function after hysterectomy. Diseases of the colon and rectum, 9369110.
https://pubmed.ncbi.nlm.nih.gov/9369110/
Maconi G, Furfaro F, Fries W, Dell'Era A, Bezzio C, Costantino G, et al. (2017). Intestinal gas and liver steatosis: a casual association? A .... Liver international : official journal of the International Association for the Study of the Liver, 27375263.
Q.
How can I identify if I have pencil thin stools?
A.
Pencil-thin stools are stools that look very narrow, similar to a pencil. They are not always a sign of a serious problem but can be checked by a doctor if you are worried.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Rex DK, & Baillie J. (2001). An old lady with pencil-thin stool. Endoscopy, 11204994.
https://pubmed.ncbi.nlm.nih.gov/11204994/
Ott DJ. (1997). Pencil-thin stools and constipation: indications for barium .... Abdominal imaging, 9157872.
Q.
How much poop can your body hold at one time?
A.
The human body can hold about 1 to 2 pounds of poop at one time, but this can vary depending on diet and bowel movement habits.
References:
Cummings JH, Bingham SA, Heaton KW, & Eastwood MA. (1992). Fecal weight, colon cancer risk, and dietary intake .... Gastroenterology, 1333426.
https://pubmed.ncbi.nlm.nih.gov/1333426/
Rose C, Parker A, Jefferson B, & Cartmell E. (2015). The Characterization of Feces and Urine: A Review .... Critical reviews in environmental science and technology, 26246784.
https://pubmed.ncbi.nlm.nih.gov/26246784/
Raahave D. (2015). Faecal retention: a common cause in functional bowel .... Danish medical journal, 25748875.
Q.
How narrow is considered too narrow for stool?
A.
Having narrow stools, like 'pencil thin' stools, is not necessarily a sign of a health problem according to some studies.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Johannsson HO, Graf W, & Påhlman L. (2005). Bowel habits in hemorrhoid patients and normal subjects. The American journal of gastroenterology, 15667500.
https://pubmed.ncbi.nlm.nih.gov/15667500/
Adejumo AC, Flanagan R, Kuo B, & Staller K. (2019). Relationship Between Recreational Marijuana Use and .... The American journal of gastroenterology, 31764090.
Q.
Is it possible for hemorrhoids to cause pencil thin stools?
A.
Hemorrhoids do not typically cause pencil thin stools. Pencil thin stools are not a sign of hemorrhoids.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Johannsson HO, Graf W, & Påhlman L. (2005). Bowel habits in hemorrhoid patients and normal subjects. The American journal of gastroenterology, 15667500.
https://pubmed.ncbi.nlm.nih.gov/15667500/
Brazell HD, Patel M, O'Sullivan DM, Mellen C, & LaSala CA. (2014). The impact of pessary use on bowel symptoms: one-year .... Female pelvic medicine & reconstructive surgery, 24566213.
Q.
Is pencil thin stool a symptom of Crohn's disease?
A.
Pencil thin stool is not a sign of Crohn's disease.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
Q.
What are the common causes of narrow stools?
A.
Narrow stools can be caused by various conditions, including obstructions in the colon or rectum, such as masses or strictures.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Chedid V, Arasoghli M, & Hashash JG. (2015). Obstructing Colonic Mass: A Case of Recurrent .... Case reports in gastrointestinal medicine, 26199767.
https://pubmed.ncbi.nlm.nih.gov/26199767/
Yoshizawa M, Mizukoshi N, Nadaya T, Kuwahara A, Kimura S, Usuki S, et al. (2022). [Preoperative Chemoradiotherapy for Advanced Rectal .... Gan to kagaku ryoho. Cancer & chemotherapy, 36732982.
Q.
What are the common causes of pencil thin stools?
A.
Pencil thin stools can be caused by changes in bowel function, such as those occurring after surgeries like hysterectomy, but they are not necessarily a sign of serious illness.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Aneese AM, Manuballa V, Amin M, & Cappell MS. (2017). Bladder urothelial carcinoma extending to rectal mucosa .... World journal of gastrointestinal endoscopy, 28690772.
https://pubmed.ncbi.nlm.nih.gov/28690772/
van Dam JH, Gosselink MJ, Drogendijk AC, Hop WC, & Schouten WR. (1997). Changes in bowel function after hysterectomy. Diseases of the colon and rectum, 9369110.
Q.
What are the potential health concerns with pencil thin stools?
A.
Pencil thin stools can sometimes be a sign of a blockage in the colon or other serious conditions, but they are not always a cause for concern on their own.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Chedid V, Arasoghli M, & Hashash JG. (2015). Obstructing Colonic Mass: A Case of Recurrent .... Case reports in gastrointestinal medicine, 26199767.
https://pubmed.ncbi.nlm.nih.gov/26199767/
Aneese AM, Manuballa V, Amin M, & Cappell MS. (2017). Bladder urothelial carcinoma extending to rectal mucosa .... World journal of gastrointestinal endoscopy, 28690772.
Q.
What are the primary causes of thin stools?
A.
Thin stools can be caused by bowel dysfunction, such as in fibromyalgia, and can also be seen in people with hemorrhoids.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Triadafilopoulos G, Simms RW, & Goldenberg DL. (1991). Bowel dysfunction in fibromyalgia syndrome. Digestive diseases and sciences, 1985007.
https://pubmed.ncbi.nlm.nih.gov/1985007/
Johannsson HO, Graf W, & Påhlman L. (2005). Bowel habits in hemorrhoid patients and normal subjects. The American journal of gastroenterology, 15667500.
Q.
What could cause a long stringy thing in my poop?
A.
A long stringy thing in poop could be due to changes in stool shape or texture, which might not always indicate a serious problem.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Stringer AM, Gibson RJ, Bowen JM, Logan RM, Yeoh AS, & Keefe DM. (2007). Chemotherapy-induced mucositis: the role .... The journal of supportive oncology, 17624050.
https://pubmed.ncbi.nlm.nih.gov/17624050/
Shafik A. (1981). Urethral discharge, constipation, and hemorrhoids. New .... Urology, 7269018.
Q.
What could cause my poop to be thinner than usual?
A.
Thin poop isn't always a sign of a serious problem. It's important to look at other symptoms and talk to a doctor if you're worried.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
Q.
What could green stringy poop in my baby indicate?
A.
Green stringy poop in babies can sometimes be mistaken for a parasitic infection, but often it is not a cause for concern.
References:
Leung FH, & Watson W. (2011). The parasite that wasn't: A case of mistaken identity - PMC. Canadian Family Physician, 3192079.
Q.
What does narrow stool look like and how can I identify it?
A.
Narrow stool, often called 'pencil thin,' appears smaller in width than usual. However, it is not necessarily a sign of any specific health issue.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
van Dam JH, Gosselink MJ, Drogendijk AC, Hop WC, & Schouten WR. (1997). Changes in bowel function after hysterectomy. Diseases of the colon and rectum, 9369110.
Q.
What does narrowing of the stool refer to in medical terms?
A.
Narrowing of the stool, also known as 'pencil thin stool,' can be related to conditions like anal stenosis, where the anal canal becomes tight and difficult to pass stool through.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Chiarelli M, Guttadauro A, Maternini M, Lo Bianco G, Tagliabue F, Achilli P, et al. (2018). The clinical and therapeutic approach to anal stenosis. Annali italiani di chirurgia, 30588920.
https://pubmed.ncbi.nlm.nih.gov/30588920/
Brisinda G, Vanella S, Cadeddu F, Marniga G, Mazzeo P, Brandara F, & Maria G. (2009). Surgical treatment of anal stenosis. World journal of gastroenterology, 19399922.
Q.
What does stringy poop indicate about my digestive health?
A.
Stringy poop, also known as low caliber stool, is not a specific sign of any disease, but if you notice changes in your bowel habits, it may be worth discussing with a doctor.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
Q.
What does the term thin caliber stools refer to?
A.
Thin caliber stools, also known as pencil-thin stools, are not necessarily a sign of a specific disease.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
Q.
What is considered a narrow stool and how is it defined?
A.
Narrow stools, often described as 'pencil-thin,' are not always a sign of a medical problem. They can occur for various reasons, including dietary changes or stress.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Rex DK, & Baillie J. (2001). An old lady with pencil-thin stool. Endoscopy, 11204994.
https://pubmed.ncbi.nlm.nih.gov/11204994/
Balar AV. (2017). Immune Checkpoint Blockade in Metastatic Urothelial Cancer. Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 28481707.
Q.
What is the significance of narrow stools in terms of health?
A.
Narrow stools are not necessarily a sign of a serious health issue.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Lee KJ, Kim JH, & Cho SW. (2005). Gabapentin reduces rectal mechanosensitivity and .... Alimentary pharmacology & therapeutics, 16268973.
https://pubmed.ncbi.nlm.nih.gov/16268973/
Raynaud F, Seifeddine A, Guy L, Escaravage L, & Boiteux JP. (1998). Use of the Valtrac ring for digestive anastomoses in urology. Progres en urologie : journal de l'Association francaise d'urologie et de la Societe francaise d'urologie, 9615930.
Q.
What should I know about narrow thin stools and their causes?
A.
Narrow, thin stools can happen for different reasons and are not always a sign of a serious problem. It's important to pay attention to any changes in bowel habits and talk to a doctor if you are concerned.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Rex DK, & Baillie J. (2001). An old lady with pencil-thin stool. Endoscopy, 11204994.
https://pubmed.ncbi.nlm.nih.gov/11204994/
van Dam JH, Gosselink MJ, Drogendijk AC, Hop WC, & Schouten WR. (1997). Changes in bowel function after hysterectomy. Diseases of the colon and rectum, 9369110.
Q.
When should I be concerned about thin stools?
A.
Thin stools can sometimes be a sign of a blockage in the colon, like a mass or a stricture, especially if it happens often. If you notice this along with other symptoms, it's a good idea to see a doctor.
References:
Borhan-Manesh F. (2009). "Low caliber stool" and "pencil thin stool" are not signs of .... Digestive diseases and sciences, 18683051.
https://pubmed.ncbi.nlm.nih.gov/18683051/
Chedid V, Arasoghli M, & Hashash JG. (2015). Obstructing Colonic Mass: A Case of Recurrent .... Case reports in gastrointestinal medicine, 26199767.
https://pubmed.ncbi.nlm.nih.gov/26199767/
Chon HK, Shin IS, Kim SW, & Lee ST. (2016). High grade anorectal stricture complicating Crohn's disease. Intestinal research, 27433152.
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