Is Diarrhea a Symptom of COVID?

The presence of a fever, sore throat, persistent cough and body aches are what most people think of when attempting to decipher if they have COVID-19 or not. Gastrointestinal symptoms, such as diarrhea, are usually an afterthought. If you find yourself on the toilet, instead of assuming it’s due to food poisoning or a stomach bug, should COVID cross your mind? This will dive deeper into the relationship between the coronavirus and diarrhea. 

Can COVID cause diarrhea?

Typically, when you eat food, your stomach turns solids into a liquid before it passes through the intestines to absorb nutrients (in the small intestine) and water (in the large intestine) to form stool. 

The reason diarrhea occurs is due to stool traveling too fast in the GI tract. This alteration in transit time allows too much water to stay in your stool, creating loose, watery bowel movements.

Diarrhea can occur for many reasons – an infection (either viral or bacterial), a food intolerance, a reaction to medications or a chronic disease (IBS or Crohn's disease). When you become infected with COVID, SARS-CoV-2 (the virus that causes COVID) attaches not only to receptors in your lungs and airways but also in the lining of your gut.

These receptors, called angiotensin-converting enzyme 2 (ACE2), are found in cell membranes of gastric glands, duodenal glands, rectal glands and in epithelial cells that line the ileum (longest part of the small intestine) and colon (biggest part of the large intestine). An inflammatory response occurs once COVID attaches to the ACE2 receptors, causing diarrhea and other GI symptoms. 

Some people, especially children, experience diarrhea as an initial COVID symptom, while for others it’s the only symptom. In one study, 16 percent of people showed only GI symptoms, of which 37 percent experienced diarrhea. 

During the initial wave of COVID, nearly a third of adults had diarrhea as a major symptom, according to the ZOE Health Data app that collects symptomatic data from millions of COVID patients. The presence of diarrhea decreased with COVID variants such as Delta and Omicron.

Since then, there have been many studies conducted on the role of diarrhea in COVID patients.

A meta-analysis of more than 18,000 COVID patients from 43 different studies found diarrhea to be the most common gastrointestinal symptom, affecting 11.5 percent of patients. Another meta-analysis of 38 studies with 8407 patients found 15.5 percent patients had at least one GI symptom, led by 11.5 percent of people who experienced diarrhea. A smaller study of 1,672 hospitalized COVID patients found an even higher prevalence of diarrhea – 40 percent had at least one GI symptom, of which 28 percent experienced diarrhea. 

Normal diarrhea vs. COVID diarrhea

Many people have wondered if diarrhea caused by COVID is different from diarrhea caused by other viral or bacterial infections. In short, the answer is no. The end result is still the same – pathogens infect cells in the GI tract and either irritate the intestines to prevent water absorption or release chemicals that create too much fluid in the bowels. In either case, stool is watery.

You may notice a change in stool color or your stool is more watery than diarrhea caused by the stomach flu or food poisoning, although that may be more indicative of the strength of infection as opposed

Green poop and COVID

Throughout the pandemic, COVID patients have taken to the internet or social media searching for answers on why their poop was green. This shouldn’t alarm you, as it’s common for your stool to change colors when having GI problems.

Simply put, the liver produces a fluid called bile to help digest fats. When food doesn’t break down in time due a viral infection, bile can pass through the GI tract and exit the body through your stool. 

Your poop may also turn yellow because of undigested lipids (fats) in your stool.

How to treat COVID diarrhea

In general, anti-diarrhea medication is one of the most common treatments for watery, liquid stools. Medications such as loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) work by slowing down your intestines so more water can be absorbed.

However, a recent study by Stanford Medicine discovered some COVID patients shed genetic material (viral RNA) through feces for up to seven months following infection. Although the sample size was small (113 people), about 13 percent were still shedding the virus four months later and 4 percent still had viral RNA in their feces after seven months.

Why does this matter? Since it’s clear the virus can linger in your GI tract, using anti-diarrhea medications may create a catch-22 – it can temporarily treat your symptoms but may also prolong the time it takes symptoms to clear up.

In addition to anti-diarrhea medications, simethicone (Gas-X) and bismuth subsalicylate can help reduce gas and bloating associated with GI symptoms.

The key in treating diarrhea, though, is to stay hydrated. Since the large intestine doesn’t absorb water like it normally does when you have diarrhea, it’s easy to lose fluids and electrolytes and become dehydrated. 

Switching to a clear liquid diet is one way to deal with diarrhea. Water, broth, juice, or low-sugar popsicles are all good choices to replenish fluids. Avoid sugary drinks as they cause your body to use more water to process glucose, which can compound dehydration. 

Slowly introduce solids that are gentle on your stomach using the BRAT acronym – bananas, rice, apples and toast. These foods are both bland to not upset your stomach and can help bind your stool to firm it up.

If you experience COVID symptoms, such as viral complications or GI issues, please contact your primary care physician for guidance on how to treat your illness. While uncommon, some COVID cases may cause severe diarrhea that leads to dehydration. It’s important to contact your doctor or head to the nearest emergency room or urgent care facility if you feel fatigued, dizzy, lightheaded or notice a decrease in urine output – all warning signs of dehydration.