What is the Purpose of Diarrhea? The Surprising Science Behind What Purpose Diarrhea Serves


We’ve all been there: dealing with the discomfort of diarrhea and searching for immediate relief. But could our bodies have a perfectly good reason for developing such a pesky symptom?

If you’ve ever wondered, “What is the purpose of diarrhea?” keep reading. We’ll explore why and how our bodies use diarrhea to preserve our health, as well as common causes and practical tips to deal with it.

What is the purpose of diarrhea?

Believe it or not, diarrhea plays a crucial role in our body’s defense system. Its primary function is to rapidly remove harmful substances from our digestive tract–be it toxins from contaminated food or dangerous pathogens causing infections.

When harmful invaders disrupt our digestive system, diarrhea increases the pace at which contents move through the intestines, preventing pathogens from settling, multiplying, and inflicting further harm.

By expediting the removal of these substances, diarrhea protects us from potentially severe complications.

Understanding the purpose diarrhea

In a pioneering new study from Brigham and Women’s Hospital, researchers studied mice with a gut infection, Citrobacter rodentium–similar to a type humans get from E. coli.

Two days after the mice got sick–even before other signs of illness appeared–they developed intestinal permeability. In the case of diarrhea, what may otherwise be called “leaky gut” appears to be a defense mechanism intended to allow in fluids and make the stool more watery, helping to flush out pathogens. Researchers also discovered that two molecules, called interleukin-22 (IL-22) and claudin-2, play a big part in this reaction.

IL-22, a molecule that increases resistance to infection and promotes immune response to pathogens, primarily targets cells in tissues like the gut to enhance their defense. Claudin-2 is a protein in the intestinal lining that is known to change intestinal permeability and, when activated, leads to diarrhea.

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The study showed that IL-22 increases claudin-2 expression, causing diarrhea as a strategic defense to eliminate invaders from the body. So, diarrhea actually plays an important role in protecting us from certain illnesses.

What are the most common causes of diarrhea?

Your body may use diarrhea as a defense mechanism in a number of different situations, including:

  • Bacterial or viral infection (these are the most common causes)
  • Difficulty digesting certain foods (food intolerance)
  • Allergic reactions to foods, like those seen in celiac disease (gluten allergies)
  • Parasitic infection from contaminated food or water
  • Side effects from medications, including antibiotics and antacids
  • Conditions affecting the intestines, such as inflammatory bowel disease (IBS)
  • Metabolic disorders, like certain thyroid issues
  • Emotional distress or anxiety
  • Rarer causes, including side effects from radiation treatments or hormone-producing tumors

What to do about diarrhea

When you’re dealing with diarrhea, it’s only natural to want to grab a banana or even over-the-counter medication for fast relief. And in light of the study mentioned above, some researchers have suggested creating therapeutics targeting claudin-2 to stop diarrhea in its tracks.

But because of its important role in fighting infections, the healthiest option is to simply let diarrhea run its course. That said, diarrhea can cause dehydration, which can be dangerous.

So, if you’re going through it, here are some tips to support your body during the process:

  • Stay hydrated. Drink more water than you normally would.
  • Get some electrolytes, through sources like electrolyte-enhanced water or no-sugar-added coconut water, since diarrhea can deplete them.
  • Avoid fried, greasy foods, and anything high in saturated or trans fats. These extra fats are broken down in the colon, which can release extra fluids and worsen diarrhea.
  • Avoid spicy foods, which can further irritate the lining of the stomach and intestines.
  • Avoid alcohol, dairy products, soda, and other carbonated or caffeinated drinks, which may make diarrhea worse.
  • Avoid sugar. Excess fructose can lead to diarrhea, especially if your digestive system is already compromised.
  • Avoid sweeteners like sorbitol, xylitol, mannitol, which can further irritate the digestive system.
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What if my diarrhea won’t go away?

Most of us have experienced diarrhea at some point, and usually, it’s a short-lived inconvenience, resolving itself within a day or two. If it lasts more than two days, it could be a sign of underlying issues like IBS, intestinal conditions such as Crohn’s disease, or even infection from parasites.

Extended or intense bouts of diarrhea can result in dehydration, the loss of crucial nutrients, and other health concerns. So, while it’s a natural bodily response, if it becomes severe or persistent, make sure to hydrate and consult a healthcare professional.

Diarrhea is no fun. But remember: it’s your body’s natural mechanism to flush out harmful invaders and recalibrate your gut’s balance. So, next time you find yourself dealing with it, remember to stay hydrated, replenish with electrolytes, and seek help if it doesn’t go away.


Symptoms & Causes of Diarrhea – NIDDK

Diarrhea – StatPearls – NCBI Bookshelf

Bacterial Diarrhea – StatPearls – NCBI Bookshelf

Bowel infections (intestinal infections) – symptoms and treatment | healthdirect

Diarrhea – Clinical Methods – NCBI Bookshelf.

Overview of the IL-1 family in innate inflammation and acquired immunity – PMC.

Consequences of dysthyroidism on the digestive tract and viscera – PMC

Food Allergy and Intolerance in IBS – PMC

Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns – PMC

Prevalence of Diarrhea, Intestinal Parasites, and Associated Factors Among Under-Five Children in Dabat District, Northwest Ethiopia: Multicenter Cross-sectional Study – PMC

Drug-induced diarrhoea

Paracellular permeability and tight junction regulation in gut health and disease | Nature Reviews Gastroenterology & Hepatology.

Related:   Foodborne Diseases: Causes, Types, Detection, & More

Use of probiotics for prevention of radiation-induced diarrhea – PMC

Differential Diagnosis and Management of Diarrhea in Patients with Neuroendocrine Tumors – PMC

Pathophysiological Mechanisms of Gastrointestinal Toxicity – PMC

The temporal relationship of daily life stress, emotions, and bowel symptoms in irritable bowel syndrome-Diarrhea subtype: A smartphone-based experience sampling study

Effects of high dose antacids on bowel motility.

Article IL-22 Upregulates Epithelial Claudin-2 to Drive Diarrhea and Enteric Pathogen Clearance

Public knowledge of dehydration and fluid intake practices: variation by participants’ characteristics – PMC

Adult Dehydration – StatPearls – NCBI Bookshelf

Oral Rehydration Therapy in the Second Decade of the Twenty-first Century – PMC

Diarrhea Caused by High-Fat and High-Protein Diet Was Associated With Intestinal Lactase-Producing Bacteria – PMC.

Capsaicin – StatPearls – NCBI Bookshelf

Gastrointestinal Disturbances Associated with the Consumption of Sugar Alcohols with Special Consideration of Xylitol: Scientific Review and Instructions for Dentists and Other Health-Care Professionals – PMC

Alcohol-related diarrhea

Artificial Sweeteners: A Systematic Review and Primer for Gastroenterologists – PMC

Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials – PMC


Carrie Solomon

Carrie Solomon is a freelance health writer, copywriter, and passionate wellness enthusiast. She’s on a mission to help wellness-focused companies educate, engage, and inspire their audiences to make the world a healthier, happier place. Learn more about her at copybycarrie.com or on LinkedIn.

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