Undigested Food in Stool: Causes and How to Manage It
Health ConditionsDigestive Health

Undigested Food in Stool: Why It Happens and What to Do About It

There are a few reasons undigested food might appear in the toilet — and they’re mostly harmless.
Undigested Food in Stool: Why It Happens and What to Do About It
Stocksy; Everyday Health
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Published on April 21, 2025
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Your body breaks down the food you eat as it travels through your digestive system, but some pieces may make a surprise reappearance in your stool (poop).

High-fiber foods like raw veggies are the most likely cause of undigested food in your stool because your body has a harder time breaking them down.

 Food pieces in stool can be fairly common, says Douglas Sprung, MD, a gastroenterologist in Altamonte Springs, Florida. “Anyone can see undigested food periodically,” he says.

But other factors, including certain medical conditions, can cause this symptom and may warrant a visit to the doctor in some cases.

Causes of Undigested Food in Stool

You may see undigested food in your stool for a number of reasons. These could be as simple as not chewing your food enough, but it can also happen as a result of some medical conditions, says Mikhail Yakubov, MD, a gastroenterologist in New York City.

High-Fiber Foods

Fiber is an important nutrient for healthy digestion, cholesterol, blood pressure, and weight maintenance. But as mentioned, the digestive tract can’t fully break down fiber-rich foods, which is why pieces of food can come out intact.

 “High-fiber foods like corn, nuts, seeds, and vegetable skins contain cellulose, which your body doesn’t fully digest,” says Dr. Yakubov. Kale, beans, and apple skins may also appear in bowel movements, Dr. Sprung adds.

Eating Too Fast

When you eat quickly, you might skimp on chewing — an important first step in the digestion process. Your stomach can’t break down larger chunks of food as easily as smaller ones, so fast eaters may see more undigested food in the toilet.

Rapid Digestion

Typically, food takes 24 to 48 hours to travel through your gastrointestinal (GI) tract.

 But sometimes your digestive system may move things along a little too fast, says Yakubov. “[This] can happen if you’re dealing with diarrhea, stress, or conditions like irritable bowel syndrome,” he adds.

Certain Health Conditions

In most cases, undigested food in stool on its own is completely harmless. In other cases, especially if you’re having other symptoms like vomiting or diarrhea, undigested food in your stool could be a sign that your body isn’t absorbing nutrients well, says Yakubov. “This can happen with conditions like celiac disease, inflammatory bowel disease, or pancreatic insufficiency.”

Health conditions that could keep your body from digesting food well include:

  • Inflammatory bowel disease (IBD), which includes conditions like Crohn’s disease and ulcerative colitis, causes inflammation and swelling in your digestive tract, which makes digesting food and absorbing nutrients difficult.

  • Pancreatic insufficiency, which means you don’t have enough digestive enzymes (natural digestive chemicals in the body) to break down the food you eat.

  • Celiac disease, which triggers your immune system to reject a protein called gluten, found in foods like wheat. This causes an inflammatory reaction in your gut that disrupts digestion.

  • Dumping syndrome, which causes your stomach to empty too quickly into your small intestine before food can be properly broken down.

  • Irritable bowel syndrome (IBS), which involves hypersensitivity of the GI tract nerves, causing pain and diarrhea.

  • Lactose intolerance, which means your body doesn’t digest lactose-containing dairy products well. When you consume them, it leads to digestive distress and disruption.

  • Small intestinal bacterial overgrowth (SIBO), which causes an unusual increase in certain bacteria in your GI tract. This can affect how well you absorb nutrients from food.

How to Manage Undigested Food in Stool

As mentioned, undigested food in stool is harmless in most cases. “If you’re otherwise feeling fine and just notice the occasional piece of undigested food (especially after eating lots of raw veggies or fiber-rich foods), there’s usually nothing to worry about,” says Yakubov.

Anything you can do to help your body digest food better will decrease the amount of food pieces you see in your bowel movements, adds Yakubov. He recommends these lifestyle changes to help:

  • Chew your food more thoroughly
  • Eat a balanced diet
  • Cook your vegetables well rather than eating them raw

When to See a Doctor

As mentioned, while pieces of undigested food in your stool can be normal, it’s a good idea to tell your healthcare provider about it if you’re having other digestive symptoms, too.

 Yakubov and Sprung recommend seeing a doctor if you experience the following symptoms alongside undigested food in your stool:

  • Frequent diarrhea
  • Liquid stools
  • Bloating
  • Nausea
  • Vomiting
  • Unexplained weight loss
  • Greasy or foul-smelling stools
  • Oily residue in the toilet bowl
  • Ongoing abdominal pain
  • Blood in stool
  • Bowel movements during sleeping hours
Undigested food in your stool is almost never a sign of an illness or malabsorption, except when the aforementioned symptoms are present, says Sprung.

 In these cases, you may need further testing to check for enzyme deficiencies, food intolerances, or conditions affecting absorption, says Yakubov.

“If you’re noticing undigested food now and then, don’t stress about it. But if it’s happening often and you’re not feeling your best, it’s worth a conversation,” says Yakubov.

The Takeaway

  • Undigested food in your stool is normal, but if it happens alongside diarrhea, vomiting, unexplained weight loss, or other symptoms, let your doctor know.
  • The most common causes of food pieces in your stool include not chewing your food enough and eating high fiber foods like raw vegetables, beans, and fruit skins.
  • You can help prevent undigested food in your stool by eating slowly, chewing thoroughly, and cooking your vegetables well.
  • If you feel concerned about undigested food in your stool, talk to your medical provider, who can help you understand what may be causing it and make a plan to address it.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Khanna S. Undigested Food in Stool: What Does It Mean? Mayo Clinic. October 12, 2023.
  2. Keendjele TPT et al. Corn? When Did I Eat Corn? Gastrointestinal Transit Time in Health Science Students. Advances in Physiology Education. March 1, 2021.
  3. Malik Z. Overview of Malabsorption. MSD Manual Consumer Version. March 2025.
  4. Malnutrition and IBD. Crohn's & Colitis Foundation.
  5. Ghodeif AO et al. Pancreatic Insufficiency. StatPearls. January 16, 2023.
  6. Celiac Disease. Cleveland Clinic. December 1, 2022.
  7. Dumping Syndrome. Cleveland Clinic. June 7, 2022.
  8. Irritable Bowel Syndrome (IBS). Johns Hopkins University.
  9. Lactose Intolerance. Cleveland Clinic. March 3, 2023.
  10. Small Intestinal Bacterial Overgrowth (SIBO) - Symptoms and Causes. Mayo Clinic. January 6, 2022.
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Ira Daniel Breite, MD

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Castle Connolly Top Doctor

Ira Daniel Breite, MD, is a board-certified internist and gastroenterologist. He is an associate professor at the Icahn School of Medicine at Mount Sinai, where he also sees patients and helps run an ambulatory surgery center.

Dr. Breite divides his time between technical procedures, reading about new topics, and helping patients with some of their most intimate problems. He finds the deepest fulfillment in the long-term relationships he develops and is thrilled when a patient with irritable bowel syndrome or inflammatory bowel disease improves on the regimen he worked with them to create.

Breite went to Albert Einstein College of Medicine for medical school, followed by a residency at NYU and Bellevue Hospital and a gastroenterology fellowship at Memorial Sloan Kettering Cancer Center. Working in city hospitals helped him become resourceful and taught him how to interact with people from different backgrounds.

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