Change in Stool Smell
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Try one of these related symptoms.
My poop smells like ammonia
Foul smelling stool and gas
Change in stool smell
Acidic smelling poop
Sour smelling stool
Sudden change in stool consistency and gas smell
Poop smells weird
Poop smells different
Poop smells like rubber
Diarrhea smells like ammonia
Funny smelling poop
Poop smells like burnt hair
About the Symptom
Changes in stool smell can be caused by the foods you eat, intolerances or allergies, infections and underlying medical conditions. Abnormally foul-smelling stools may also be a sign of an underlying disease, such as celiac disease, Crohn's disease, cystic fibrosis, and intestinal infections.
Possible Causes
Generally, Change in stool smell can be related to:
- Cystic Fibrosis (CF)
Cystic fibrosis (CF) is a genetic disorder that causes severe damage to the lungs, digestive system, and other organs in the body.
Doctor's Diagnostic Questions
Your doctor may ask these questions to check for this symptom:
- Does your stool have a different or strange smell?
- Do your stools have an offensive smell?
- Do your stools smell sour?
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).
Yoshinori Abe, MD (Internal Medicine)
Dr. Abe graduated from The University of Tokyo School of Medicine in 2015. He completed his residency at the Tokyo Metropolitan Health and Longevity Medical Center. He co-founded Ubie, Inc. in May 2017, where he currently serves as CEO & product owner at Ubie. Since December 2019, he has been a member of the Special Committee for Activation of Research in Emergency AI of the Japanese Association for Acute Medicine. | | Dr. Abe has been elected in the 2020 Forbes 30 Under 30 Asia Healthcare & Science category.
Content updated on Jan 29, 2025
Following the Medical Content Editorial Policy
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People with similar symptoms also use Ubie's symptom checker to find possible causes
- Acidic smell from bowel movements
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- Poop has a chemical smell
- My stool smells foul
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- Acidic smelling stool
- Really stinky poop
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FAQs
Q.
What Causes Poop Smells Like Sewer Gas?
A.
Poop can smell like sewer gas when changes in digestion or infections in your gut cause bacteria to make extra stinky chemicals.
References:
Pezzilli R. Chronic pancreatitis: maldigestion, intestinal ecology and intestinal inflammation. World J Gastroenterol. 2009 Apr 14;15(14):1673-6. doi: 10.3748/wjg.15.1673. PMID: 19360910; PMCID: PMC2668772.
Mogilnicka I, Bogucki P, Ufnal M. Microbiota and Malodor-Etiology and Management. Int J Mol Sci. 2020 Apr 20;21(8):2886. doi: 10.3390/ijms21082886. PMID: 32326126; PMCID: PMC7215946.
Mada PK, Alam MU. Clostridioides difficile infection. [Updated 2024 Apr 10]. In: StatPearls [Internet].
Q.
Why My Poop Smells Like Ammonia?
A.
Poop that smells like ammonia can happen when there isn’t enough water in your body, or when your gut or liver makes extra ammonia from breaking down protein.
References:
van Nieuwenhoven MA, Vriens BE, Brummer RJ, Brouns F. Effect of dehydration on gastrointestinal function at rest and during exercise in humans. Eur J Appl Physiol. 2000 Dec;83(6):578-84. doi: 10.1007/s004210000305. PMID: 11192068.
Atluri DK, Prakash R, Mullen KD. Pathogenesis, diagnosis, and treatment of hepatic encephalopathy. J Clin Exp Hepatol. 2011 Sep;1(2):77-86. doi: 10.1016/S0973-6883(11)60126-6. Epub 2011 Nov 9. PMID: 25755319; PMCID: PMC3940085.
Zhao J, Zhang X, Liu H, Brown MA, Qiao S. Dietary Protein and Gut Microbiota Composition and Function. Curr Protein Pept Sci. 2019;20(2):145-154. doi: 10.2174/1389203719666180514145437. PMID: 29756574.
Q.
Why Does My Poop Smells Like Burnt Hair?
A.
Your poop might smell like burnt hair because changes in your gut bacteria can create unusual chemicals that give off a strong, odd odor.
References:
Engen PA, Green SJ, Voigt RM, Forsyth CB, Keshavarzian A. The Gastrointestinal Microbiome: Alcohol Effects on the Composition of Intestinal Microbiota. Alcohol Res. 2015;37(2):223-36. PMID: 26695747; PMCID: PMC4590619.
Bosch S, Wintjens DSJ, Wicaksono A, Pierik M, Covington JA, de Meij TGJ, de Boer NKH. Prediction of Inflammatory Bowel Disease Course Based on Fecal Scent. Sensors (Basel). 2022 Mar 17;22(6):2316. doi: 10.3390/s22062316. PMID: 35336485; PMCID: PMC8948784.
Wolf, P.G., Cowley, E.S., Breister, A. _et al._ Diversity and distribution of sulfur metabolic genes in the human gut microbiome and their association with colorectal cancer._Microbiome_ 10, 64 (2022). https://doi.org/10.1186/s40168-022-01242-x
Q.
Why Does My Poop Smell So Bad?
A.
Foul-smelling poop can be related to your diet, digestive issues, or gut infections.
References:
https://www.ncbi.nlm.nih.gov/books/NBK218764/
https://www.ncbi.nlm.nih.gov/books/NBK218764/
Nelkowska DD. Treating irritable bowel syndrome through an interdisciplinary approach. Ann Gastroenterol. 2020 Jan-Feb;33(1):1-8. doi: 10.20524/aog.2019.0441. Epub 2019 Nov 29. PMID: 31892791; PMCID: PMC6928481.
Dalal RS, Allegretti JR. Diagnosis and management of Clostridioides difficile infection in patients with inflammatory bowel disease. Curr Opin Gastroenterol. 2021 Jul 1;37(4):336-343. doi: 10.1097/MOG.0000000000000739. PMID: 33654015; PMCID: PMC8169557.
Q.
Why Does My Poop Smell Sweet?
A.
Sweet-smelling poop may happen when changes in your body, such as high blood sugar or shifts in your gut bacteria, cause unusual chemicals to be made during digestion.
References:
Kitabchi AE, Umpierrez GE, Miles JM, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009 Jul;32(7):1335-43. doi: 10.2337/dc09-9032. PMID: 19564476; PMCID: PMC2699725.
Di Rienzi SC, Britton RA. Adaptation of the Gut Microbiota to Modern Dietary Sugars and Sweeteners. Adv Nutr. 2020 May 1;11(3):616-629. doi: 10.1093/advances/nmz118. PMID: 31696209; PMCID: PMC7231582.
Elhawary NA, AlJahdali IA, Abumansour IS, Elhawary EN, Gaboon N, Dandini M, Madkhali A, Alosaimi W, Alzahrani A, Aljohani F, Melibary EM, Kensara OA. Genetic etiology and clinical challenges of phenylketonuria. Hum Genomics. 2022 Jul 19;16(1):22. doi: 10.1186/s40246-022-00398-9. PMID: 35854334; PMCID: PMC9295449.
Kang DY, Kim H, Ko S, Kim H, Shinn J, Kang MG, Byeon SJ, Choi JH, Shin SY, Kim HS. Sodium-Glucose Cotransporter-2 Inhibitor-Related Diabetic Ketoacidosis: Accuracy Verification of Operational Definition. J Korean Med Sci. 2022 Feb 21;37(7):e53. doi: 10.3346/jkms.2022.37.e53. PMID: 35191230; PMCID: PMC8860766.
Q.
Why Does My Poop Smell Like Sulfur?
A.
Your poop can smell like sulfur when certain foods, supplements, or gut problems cause your gut bacteria to make extra sulfur compounds.
References:
Slavin J. Fiber and prebiotics: mechanisms and health benefits. Nutrients. 2013 Apr 22;5(4):1417-35. doi: 10.3390/nu5041417. PMID: 23609775; PMCID: PMC3705355.
Philpott HL, Nandurkar S, Lubel J, Gibson PR. Drug-induced gastrointestinal disorders. Frontline Gastroenterol. 2014 Jan;5(1):49-57. doi: 10.1136/flgastro-2013-100316. Epub 2013 Jun 19. PMID: 28839751; PMCID: PMC5369702.
Lee SH, Kwon JE, Cho ML. Immunological pathogenesis of inflammatory bowel disease. Intest Res. 2018 Jan;16(1):26-42. doi: 10.5217/ir.2018.16.1.26. Epub 2018 Jan 18. PMID: 29422795; PMCID: PMC5797268.
Tolkien Z, Stecher L, Mander AP, Pereira DI, Powell JJ. Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis. PLoS One. 2015 Feb 20;10(2):e0117383. doi: 10.1371/journal.pone.0117383. PMID: 25700159; PMCID: PMC4336293.
Moon JY, Kye BH, Ko SH, Yoo RN. Sulfur Metabolism of the Gut Microbiome and Colorectal Cancer: The Threat to the Younger Generation. Nutrients. 2023 Apr 19;15(8):1966. doi: 10.3390/nu15081966. PMID: 37111185; PMCID: PMC10146533.
Q.
Why Does My Poop Smell Like Coffee?
A.
Drinking coffee can affect your digestion, and some of its strong aromatic compounds might pass through your body, making your poop smell like coffee.
References:
Nehlig A. Effects of Coffee on the Gastro-Intestinal Tract: A Narrative Review and Literature Update. Nutrients. 2022 Jan 17;14(2):399. doi: 10.3390/nu14020399. PMID: 35057580; PMCID: PMC8778943.
Q.
Why Does My Poop Smell Like Weed?
A.
Poop that smells like weed may be related to how certain plant chemicals, like those in cannabis, change the way your gut works.
References:
Goyal H, Singla U, Gupta U, May E. Role of cannabis in digestive disorders. Eur J Gastroenterol Hepatol. 2017 Feb;29(2):135-143. doi: 10.1097/MEG.0000000000000779. PMID: 27792038.
Santhiravel S, Bekhit AEA, Mendis E, Jacobs JL, Dunshea FR, Rajapakse N, Ponnampalam EN. The Impact of Plant Phytochemicals on the Gut Microbiota of Humans for a Balanced Life. Int J Mol Sci. 2022 Jul 23;23(15):8124. doi: 10.3390/ijms23158124. PMID: 35897699; PMCID: PMC9332059.
Q.
Why Does My Poop Smell Like Metal?
A.
Your poop may smell like metal because iron, from supplements or bleeding, changes the way your gut works and creates a metallic odor.
References:
Bloor SR, Schutte R, Hobson AR. Oral Iron Supplementation—Gastrointestinal Side Effects and the Impact on the Gut Microbiota. _Microbiology Research_. 2021; 12(2):491-502. https://doi.org/10.3390/microbiolres12020033
DiGregorio AM, Alvey H. Gastrointestinal Bleeding. [Updated 2023 Jun 5]. In: StatPearls [Internet].
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