SpecialtyGastroenterology, general surgery

Steatorrhea (or steatorrhoea) is the presence of excess fat in feces. Stools may be bulky and difficult to flush, have a pale and oily appearance, and can be especially foul-smelling.[1] An oily anal leakage or some level of fecal incontinence may occur. There is increased fat excretion, which can be measured by determining the fecal fat level. The definition of how much fecal fat constitutes steatorrhea has not been standardized.[citation needed]


Impaired digestion or absorption can result in fatty stools. Possible causes include exocrine pancreatic insufficiency, with poor digestion from lack of lipases, loss of bile salts, which reduces micelle formation, and small intestinal disease-producing malabsorption. Various other causes include certain medicines that block fat absorption or indigestible or excess oil/fat in diet.[citation needed]

The absence of bile secretion can cause the feces to turn gray or pale. Bile is responsible for the brownish color of feces. In addition to this, bile also plays a role in fat absorption, where dietary lipids are combined so that pancreatic lipases can hydrolyze them before going towards the small intestine. Without bile acids, this pathway would have a hard time occurring, which would lead to fat malabsorption and make steatorrhea more probable to occur.[2] Other features of fat malabsorption may also occur such as reduced bone density, difficulty with vision under low light levels, bleeding, bruising, and slow blood clotting times.[1]

Associated diseases


Orlistat (also known by trade names Xenical and Alli) is a diet pill that works by blocking the enzymes that digest fat. As a result, some fat cannot be absorbed from the gut and is excreted in the feces instead of being metabolically digested and absorbed, sometimes causing oily anal leakage.[6][7][8] Vytorin (ezetimibe/simvastatin) tablets can cause steatorrhea in some people.[6][8]

Excess whole nuts in diet

Some studies have shown that stool lipids are increased when whole nuts are eaten, compared to nut butters, oils or flour[9] and that lipids from whole nuts are significantly less well absorbed.[10]

Natural fats

Consuming jojoba oil has been documented to cause steatorrhea and anal leakage because it is indigestible.[11]

Consuming escolar and oilfish (sometimes mislabelled as butterfish) will often cause steatorrhea, also referred to as gempylotoxism or gempylid fish poisoning or keriorrhea.[12]

Artificial fats

The fat substitute Olestra, used to reduce digestible fat in some foods, was reported to cause leakage in some consumers during the test-marketing phase. As a result, the product was reformulated before general release to a hydrogenated form that is not liquid at physiologic temperature. The U.S. Food and Drug Administration warning indicated excessive consumption of Olestra could result in "loose stools"; however, this warning has not been required since 2003.[7][13]


Steatorrhea should be suspected when the stools are bulky, floating and foul-smelling.[1] Specific tests are needed to confirm that these properties are in fact due to excessive levels of fat. Fats in feces can be measured over a defined time (often five days).[14] Other tests include the (13)C-mixed triglycerides test and fecal elastase, to detect possible fat maldigestion due to exocrine pancreatic insufficiency,[14] or various specific tests to detect other causes of malabsorption such as celiac disease.[15]


Treatments are mainly correction of the underlying cause, as well as digestive enzyme supplements.[16]

See also


  1. ^ a b c d e f g Adam S Cheifetz; Alphonso Brown; Michael Curry; Alan C Moss (10 Mar 2011). Oxford American Handbook of Gastroenterology and Hepatology. Oxford University Press. p. 234. ISBN 9780199830121.
  2. ^ Azer, S. A., & Sankararaman., S. (2023, May 16). Steatorrhea . National Library of Medicine. .
  3. ^ Lindkvist B (2013). "Diagnosis and treatment of pancreatic exocrine insufficiency". World J. Gastroenterol. (Review). 19 (42): 7258–66. doi:10.3748/wjg.v19.i42.7258. PMC 3831207. PMID 24259956.
  4. ^ Moutzouri, Elisavet; Elisaf, Moses; Liberopoulos, N. Evangelos (2011). "Hypocholesterolemia". Current Vascular Pharmacology. 9 (2): 200–12. doi:10.2174/157016111794519354. PMID 20626336.
  5. ^ Dogliotti, L; Tampellini, M; Stivanello, M; Gorzegno, G; Fabiani, L (2001). "The clinical management of neuroendocrine tumors with long-acting repeatable (LAR) octreotide: comparison with standard subcutaneous octreotide therapy". Annals of Oncology. 12 (Suppl 2): S105–9. doi:10.1093/annonc/12.suppl_2.s105. PMID 11762334.
  6. ^ a b Squires, Sally (2006-01-24). "Weighing a Pill For Weight Loss". Washington Post. Retrieved 2007-07-06. While the Food and Drug Administration (FDA) still must approve the switch, the agency often follows the advice of its experts. If it does, Orlistat (xenical) -- currently sold only by prescription -- could be available over-the-counter (OTC) later this year. But it's important to know that the weight loss that's typical for users of the drug -- 5 to 10 percent of total weight -- will be less than many dieters expect. And many consumers may be put off by the drug's significant gastrointestinal side effects, including flatulence, diarrhea, and anal leakage.
  7. ^ a b "Frito-Lay Study: Olestra Causes "Anal Oil Leakage"". Center for Science in the Public Interest. February 13, 1997. Retrieved 2007-07-07. The Frito-Lay report states: "The anal oil leakage symptoms were observed in this study (3 to 9% incidence range above background), as well as other changes in elimination. ... Underwear spotting was statistically significant in one of two low-level consumer groups at a 5% incidence above background." Despite those problems, the authors of the report concluded that olestra-containing snacks "should have a high potential for acceptance in the marketplace."
  8. ^ a b "The Word Is 'Leakage'. Accidents may happen with a new OTC diet drug". Newsweek. June 25, 2007. Archived from the original on 2007-06-18. Retrieved 2007-06-21. GlaxoSmithKline has a tip for people who decide to try Alli, the over-the-counter weight-loss drug it is launching with a multimillion-dollar advertising blitz—keep an extra pair of pants handy. That's because Alli, a lower-dose version of the prescription drug Xenical, could (cue the late-night talk-show hosts) make you soil your pants. But while Alli's most troublesome side effect, anal leakage, is sure to be good for a few laughs, millions of people who are desperate to take off weight may still decide the threat of an accident is worth it.
  9. ^ Traoret, C J; Lokko, P; Cruz, A C R F; Oliveira, C G; Costa, N M B; Bressan, J; Alfenas, R C G; Mattes, R D (2007). "Peanut digestion and energy balance". International Journal of Obesity. 32 (2): 322–8. doi:10.1038/sj.ijo.0803735. PMID 17912269.
  10. ^ Hollis, James; Mattes, Richard (2007). "Effect of chronic consumption of almonds on body weight in healthy humans". British Journal of Nutrition. 98 (3): 651–6. doi:10.1017/S0007114507734608. PMID 17445351.
  11. ^ Place, A. R. (1992). "Comparative aspects of lipid digestion and absorption: Physiological correlates of wax ester digestion". The American Journal of Physiology. 263 (3 Pt 2): R464–71. doi:10.1152/ajpregu.1992.263.3.R464. PMID 1415629.
  12. ^ Bad Bug Book - Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: Gempylotoxin, FDA
  13. ^ "Reported medical side-effects of Olestra according to Procter and Gamble studies". Center for Science in the Public Interest. Archived from the original on 2007-07-02. Retrieved 2007-06-21. Olestra sometimes causes underwear staining associated with "anal leakage." Olestra sometimes causes underwear staining. That phenomenon may be caused most commonly by greasy, hard-to-wipe-off fecal matter, but occasionally also from anal leakage (leakage of liquid olestra through the anal sphincter).
  14. ^ a b Lindkvist, B (14 November 2013). "Diagnosis and treatment of pancreatic exocrine insufficiency". World Journal of Gastroenterology. 19 (42): 7258–66. doi:10.3748/wjg.v19.i42.7258. PMC 3831207. PMID 24259956.
  15. ^ Rubio-Tapia, A; Hill, ID; Kelly, CP; Calderwood, AH; Murray, JA; American College of, Gastroenterology. (May 2013). "ACG clinical guidelines: diagnosis and management of celiac disease". The American Journal of Gastroenterology. 108 (5): 656–76, quiz 677. doi:10.1038/ajg.2013.79. PMC 3706994. PMID 23609613.
  16. ^ Azer SA, Sankararaman S (January 2021). "Steatorrhea". National Center for Biotechnology Information, U.S. National Library of Medicine. PMID 31082099. Retrieved 3 October 2021.