Diarrhea Concerns

Why Does Diarrhea Smell?

By May 3, 2018 No Comments
Why Does Diarrhea smell

It’s a safe bet to say that all stool smells unpleasant, but when experiencing diarrhea, the smell can be worse than normal. There are several reasons why your diarrhea tends to smell, and in this article, you’ll learn why.

Why Does Poop Smell Bad?

Before getting into diarrhea, let’s take a quick look at what gives normal stool its characteristic odor.

Stool is made up of a combination of dead cells, undigested food, mucus, and bacteria, some of which give off sulfurous compounds that often carry an odor. While this smell is usually normal, some things can cause poop to take on an abnormal smell, such as stool that has stayed in the colon for too long (due to constipation, for example), medication, or an infection.

Why Does Diarrhea Smell Bad?

You have probably noticed that your diarrhea smells worse than a regular bowel movement. Usually, your smelly diarrhea will resolve itself with proper hydration and rest, but there are cases when smelly diarrhea signifies a more serious problem.

Bacteria, Viruses and Parasites

Diarrhea is often caused by your body’s natural immune response to an unwanted intruder in your digestive tract. Inflammation of the stomach and digestive tract can occur due to bacteria in foods such as Salmonella or E. coli as well as viruses and parasites. All these intruders can lead to foul-smelling diarrhea and will frequently come with cramping and abdominal pain.


The inability to properly absorb nutrients from foods (malabsorption) is not uncommon and could be due to a variety of factors. Overuse of antibiotics, a diet high in processed and packaged foods, chronic stress, food allergies and intolerances, conditions such as IBD and IBS are some of the most common causes. Symptoms of malabsorption can be flatulence, smelly stool and diarrhea, sometimes alternating with constipation.


Perhaps the easiest cause of smelly diarrhea to pinpoint is a medication or supplement you are taking. Antibiotics and other OTC and prescription medications could cause overly smelly diarrhea, as can something as simple as a multivitamin. If you’ve recently begun a new medication and think this could be the cause of foul-smelling diarrhea, talk with your doctor.

What to Do About It

To prevent unusual smelling diarrhea, avoid food you might be intolerant or allergic to and work with a healthcare practitioner to undergo an elimination diet or do allergy testing. Handle food hygienically in your kitchen and know what to avoid when traveling.

As with any case of diarrhea (smelly or not), if you also experience symptoms of black, bloody or tarry stool or a high fever, it’s best to call your doctor.

DiaResQ Team

About DiaResQ Team

The DiaResQ Team consists of passionate nutritionists, doctors, and philanthropists. Based out of Boulder, CO, we strive to provide our readers with up to date, helpful information about diarrhea, hydration, healthy foods, and travel.

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