A GI doctor describes benign causes of oily or greasy bowel movements.

Do your stools look slimy, oily or greasy? 

If they appear different lately, you should see a gastroenterologist, since only a doctor can determine for sure what the cause is.

Benign Causes

“Greasy or oily stools, assuming one is not ingesting mineral oil, etc., is often a sign of fat malabsorption,” says Michael Blume, MD, a gastroenterologist at MedStar Good Samaritan Hospital, Baltimore.

“This can have many causes, including certain infections, as well as small bowel or pancreatic problems.

“Determining the cause often involves taking a detailed history as well as some diagnostic testing.”

What about IBS?

“One needs to differentiate oily looking stools and mucous in the stool,” says Dr. Blume.

“Many people with IBS complain of having mucous in their stools and that their stools look slimy.”

Pancreatic Problems

“One usually malabsorbs fat (this is what makes stools oily) if there is a problem with pancreatic function, such as with chronic pancreatitis, or from problems in the small intestine where fats get absorbed, such as with celiac disease, certain infections, such as Giardiasis, small bowel bacterial overgrowth, or other inflammatory diseases.”

In practice for 20+ years, Dr. Blume treats over 65 conditions including abdominal pain, appetite loss, blood in stool, celiac disease, colon cancer, esophageal and liver disease, gas and IBS.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.