What Is Diarrhea

Infectious Diseases

What is Diarrhea? 

Lately I’ve been seeing a lot of babies and toddlers with diarrhea; many having had diarrhea for a week or more. When a baby has diarrhea, parents naturally become concerned about hydration and weight loss. These are valid concerns. But generally, diarrhea in babies and children will not cause ill effects, apart from those extra diaper changes and having to help your child to the toilet frequently.

Diarrhea is one of the most common things I see in the emergency department and in the office. Most children with diarrhea have viral infections called gastroenteritis. Vomiting and fever may accompany diarrhea. And though it is usually benign, dehydration is, as with babies, a legitimate concern.


Diarrhea is one of the most common things I see in the emergency department and in the office. 

What is diarrhea?

Diarrhea is defined as watery stools that are often more frequent than normal bowel movements.

Stomach flu

The majority of people call viral gastroenteritis the ‘stomach flu’ and know it for its contagiousness. It often travels through camps, classrooms or day care centers. Rotavirus is one of the most common types of stomach flu, though it is decreasing in frequency as infants are vaccinated against it. Outbreaks of gastroenteritis typically occur in the winter and early spring, while viruses like the Coxsackie virus usually break out during the summer months.

Signs of the flu

Children typically have:

•     Reduced appetite

•     Fever

•     Nausea

•     Vomiting

•     Weight loss

•     Risk of dehydration

I find that the best way to tell if a child is dehydrated is by checking for dry mouth, less glossy eyes, lethargy and decreased voiding. See your doctor if your child looks like this.

Causes of gastroenteritis

A variety of different viruses, bacteria and parasites can cause diarrhea. Depending on where you are in the world, there are different bugs that cause diarrhea.

No matter where, infectious gastroentiritis is most commonly acquired from person to person contact, contaminated food or water.

Infections that cause diarrhea are generally very contagious. Less than stellar hand and toilet hygiene can lead to contamination and infection of others. Someone’s hands, surfaces such as chairs, changing tables, toilets and toys can all harbor the bug. With children frequently putting their fingers in their mouths, infections are easy to acquire.

Less common causes such as celiac disease, thyroid conditions and inflammatory bowel disease also exist. If your child has recurrent or frequent diarrhea, please see your doctor.

Infections that cause diarrhea are generally very contagious. 


Bacteria that cause gastroenteritis, include:

  1. Ecoli – usually through contaminated food or water such as undercooked hamburgers. Some children will get particularly ill, with the possibility of kidney damage, called Hemolytic Uremic Syndrome. Luckily, this is rare.
  2. Giardia – otherwise called ‘beaver fever’, it is often caught in contaminated water supplies, day care centers, aquariums, lakes and swimming pools.
  3. Salmonella – usually from undercooked eggs and chicken, most commonly in the summer (pasta salad anyone?).
  4. Campylobacter- undercooked chicken is the culprit here, also during the summer

How long is stomach flu contagious?

You can catch gastroenteritis from anyone who is vomiting or has diarrhea due to the illness. It is spread through a fecal-oral route, meaning contamination from their stool. So keep your hands clean and ensure the same for your kids!

To learn more about what to do when you have diarrhea 

Dr. Dina Kulik, MD, FRCPC, PEM

Written By: Dr. Dina Kulik, MD, FRCPC, PEM

Dina is a wife, mother of 4, and adrenaline junky. She loves to share children’s health information from her professional and personal experience. More About Dr Dina.

You might also enjoy

Symptoms of a Bladder Infection in Kids

Urinary tract infections are prevalent in kids — especially if you have an infant in diapers or an older child that holds in their urine for more extended periods (like in the classroom or during extracurricular activities). This is especially true for a constipated toddler who is less able to communicate the issue.

Causes of Sore Throat in Kids Including Viral Pharyngitis and Strep Throat

Causes of Sore Throat in Kids Including Viral Pharyngitis and Strep Throat

Is your kid not eating and drinking? What can be the possible reason? Perhaps your child has a sore throat, viral pharyngitis, or strep throat. Sore throat is medically known as “pharyngitis. This is the inflammation of the pharynx. Usually, we see viral pharyngitis or sore throat caused by viral infections. Other times we see pharyngitis as a result of a bacterial infection like strep throat.

Stomach Flu Treatment in Kids – What to Know and Do

Stomach Flu Treatment in Kids – What to Know and Do

Stomach Flu in children – or viral gastroenteritis – can be unsettling and something that all parents dread. However, it generally just requires hydration to best combat the illness. If your child is not eating, it can be ok as long as they are drinking plenty of fluids.

Dr. Dina Kulik - Subscribe to my Blog
Dr Dina Kulik - Kids Health blog

The general information provided on the Website is for informational purposes and is not medical advice.

Do NOT use this Website for medical emergencies.

If you have a medical emergency, call a physician or qualified healthcare provider, or CALL 911 immediately. Under no circumstances should you attempt self-treatment based on anything you have seen or read on this Website. Always seek the advice of your physician or other licensed and qualified health provider in your jurisdiction concerning any questions you may have regarding any information obtained from this Website and any medical condition you believe may be relevant to you or to someone else. Never disregard professional medical advice or delay in seeking it because of something you have read on this Website.

Success! Check Your Inbox

Success! Check Your Inbox

Success! Check Your Inbox

COVID Toolbox

Success! Check Your Inbox

Dr Dina Kulik - Kids Health blog


Success! Thanks for Subscribing!

Dr Dina Kulik - Kids Health blog


Success! Thanks for Subscribing!

Dr Dina Kulik - Kids Health - Constipation Management

Success! Check Your Inbox