If you’re suffering from diarrhea, you may be wondering what is causing it. Understanding what is causing your diarrhea is the key to finding relief. In many cases, the way that diarrhea is treated depends on the cause.

If you’ve been having diarrhea for 14 days or less, then the most likely culprits are an infection, something in your diet, stress, menstruation, running, or starting a new medication.

Infections and travel:

Infections with bacteria, viruses, or parasites are a common cause of diarrhea, especially during travel. Diarrhea caused by a viral infection is also called the “stomach flu,” although it’s not actually caused by a flu virus. Common diarrhea-causing viruses include Norwalk virus and rotavirus. Bacteria that often cause diarrhea include E. coli, salmonella, and campylobacter. You can become infected through contaminated food or drinks, by touching contaminated surfaces, or by close contact with an infected person. To protect yourself from infection, wash your hands before you eat or touch your face, and after you go to the washroom. When traveling, avoid ice cubes; drink only bottled water, pop, or beer; peel your own fruit; eat only food that is well-cooked and piping hot; and avoid shellfish and street vendor food.

Food and overindulgence:

As you’ve already seen, food can carry infections that can cause diarrhea. But did you know that you can also get diarrhea from the food itself? Artificial sweeteners (e.g., mannitol and sorbitol) found in diet or “sugar-free” foods can lead to diarrhea if you eat too much of them. These sweeteners pull extra water into your bowels, which makes your stools more watery, leading to diarrhea. Food allergies and intolerances, such as lactose or gluten intolerance, can also cause diarrhea. You may have a food allergy if you often have diarrhea after eating a certain type of food. As well, overindulgence in food, especially spicy foods, foods high in sugar, and foods containing artificial sweeteners (such as sorbitol), can cause diarrhea. Overindulgence in alcohol can also lead to diarrhea. Remember, it is better to have everything in moderation.


Stress and nervousness can cause diarrhea. What’s the connection between stress and diarrhea? Stress can make the bowels move faster. This leaves less time for water to be reabsorbed into your body, leading to watery stools.

Menstruation: Sometimes, diarrhea can be linked to a woman’s menstrual cycle. Diarrhea may appear just before or during menstruation.


Runners may experience “runner’s diarrhea” – loose bowel movements that happen during or just after a run. We don’t know exactly what causes runner’s diarrhea, but it’s believed that the action of running may stimulate bowel activity or make food pass more quickly through the digestive system.


Sometimes a new medication can cause diarrhea. Antibiotics can often cause diarrhea that starts a couple of days after you start the medication and stops when you finish taking it. Certain medications for diabetes, heart conditions, cancer, and HIV can also lead to diarrhea. Talk to your doctor or pharmacist about which of the medications you are taking may be associated with diarrhea.

If you’ve been having diarrhea for 2 weeks or less, think about recent changes or new things in your life. This can help you pinpoint the cause.

Diarrhea lasting more than 2 weeks may be a sign of an underlying health problem. See your doctor to find out what may be causing your diarrhea. Possible suspects include irritable bowel syndrome (IBS), inflammatory bowel disease, poor blood flow to the bowels, problems absorbing nutrients, a long-standing infection, or a food allergy or intolerance. Long-standing diarrhea can also be caused by chemotherapy and radiation.

What can you do to find diarrhea relief?

The first step is to decide whether you need to see a doctor or not.

You should see a doctor if:

  • you have a fever over 38.5°C or 101.3°F
  • you have severe stomach pain, bloody diarrhea, or black stools
  • your stools are soft and yellow
  • your stools are grey, white, or greasy
  • you’re taking an antibiotic or another new medication
  • you can’t keep fluids down because of vomiting
  • you’re having more than 6 loose stools each day
  • you are dehydrated (weak, thirsty, dizzy, dry mouth, decreased urination)
  • your diarrhea has lasted more than 48 hours (or 24 hours for babies)

Children should be brought to a doctor if they have any of the symptoms above, or if they have been vomiting for more than 4 hours or are under 6 months of age.

Otherwise, you can treat your own diarrhea at home.

Here’s how to manage your diarrhea:

Try an over the counter treatment. There are a number of over the counter treatments available for diarrhea relief. They include loperamide (IMODIUM™), attapulgite (KAOPECTATE®), and bismuth subsalicylate (PEPTO-BISMOL®). For relief of diarrhea as well as the symptoms of gas, cramps and bloating, loperamide plus simethicone (IMODIUM™ ADVANCED) is available. Loperamide helps with the diarrhea, while simethicone helps with the gas.

How do these medications work? Normally, water is reabsorbed as food passes through your bowels. With diarrhea, the bowels are moving too quickly for enough water to be reabsorbed, so the liquid stays in the stools, making them loose and watery. Each diarrhea medication works on this process in a slightly different way. Loperamide works by bringing the movement of the bowels back to a more normal level. This is important because diarrhea often reduces your ability to reabsorb water and absorb nutrients. Attapulgite absorbs the extra liquids in the bowel, which helps make stools more solid. It can be used for up to 2 days. Bismuth works by decreasing inflammation, killing certain bacteria that can cause diarrhea, and blocking the body from releasing more fluid into the bowels.

Don’t get dehydrated.

Dehydration is one of the dangers of diarrhea. If severe enough, diarrhea can lead to fainting, an irregular heartbeat, and other complications. Rehydrating yourself when you have diarrhea is an essential part of treating your diarrhea to lower your risk of dehydration. Dehydration happens because your body loses water and important salts called electrolytes more quickly when you have diarrhea. You can stay hydrated by drinking plenty of clear fluids. Children and seniors are at a higher risk of getting dehydrated, so it’s very important that they stay well hydrated when they have diarrhea. Children and seniors may need a special rehydration drink (such as Gastrolyte® or Pedialyte®), available from your local pharmacy or grocery store. Talk to your pharmacist to find out how much of the rehydration drink (also called rehydration solution) they need to consume each day.

Call your doctor if things don’t improve. Usually, your diarrhea will improve in a day or two. But if things change and you notice any of the symptoms listed above (such as high fever, bloody stools, or severe stomach pain), if you can’t seem to drink enough fluid to stay hydrated, or if the treatments you have tried do not seem to be working, contact your doctor as soon as possible. Depending on your situation, your doctor may recommend other treatments, including prescription medications.

Facts about diarrhea and your digestive system

People with diarrhea caused by certain infections can lose up to 20 liters of fluids per day.
A bout of diarrhea typically lasts for 1 to 2 days. But some people can have diarrhea that lasts much longer, due to underlying health conditions.
The average human intestine is about 8 meters long.
Facts about diarrhea causes:

You may have heard about recent hospital outbreaks of a serious type of diarrhea called C. difficile colitis, which can cause fever, abdominal pain, and severe dehydration. But did you know that although it does not usually affect healthy people, healthy people can still spread the infection if they do not wash their hands properly?
If you suffer from frequent diarrhea, you may have a food allergy. Allergies to milk products (lactose intolerance) and wheat (gluten intolerance) can cause diarrhea.
Facts about diarrhea treatments:

You may have heard it’s better to let diarrhea run its course rather than treating it. But except in a few cases where you should see your doctor (see “How to find diarrhea relief” for more information), you can treat your diarrhea at home with nonprescription medications.

“Colon cleansing” is often touted as a cure for all kinds of illnesses, including diarrhea. But colon cleansing regimens often contain large amounts of laxatives that can lead to severe diarrhea and dehydration. They are generally not recommended unless you need to clean out your bowel before a surgery or medical test.

If you have questions about diarrhea or how to treat it, talk to your doctor or pharmacist.

Compliance HelpLine
QR Code for Ethics Point Site
We encourage employees, medical staff, vendors, patients, and business partners to report to Janice Stewart, Compliance Officer at 516.266.5014 or the Compliance HelpLine any actual or suspected violations of the Center’s policies and procedures and/or federal or state law. Calls received by the Compliance HelpLine are most often inquiries but can sometimes be reports of potential misconduct. Our investigatory process includes many methods to determine whether any misconduct occurred. Compliance takes all calls seriously. Inquiries are reviewed by the Compliance Officer and may also be reviewed by other applicable departments.
The Center’s Compliance HelpLine is available 24 hours a day, even days a week. Compliance HelpLine callers may remain anonymous and those who choose to give their name will have their identities protected to the extent allowed by law. The Compliance HelpLine has multi-lingual operators who can take reports from individuals whose first language is not English. The Compliance HelpLine can be reached by calling (800) 894-3226 or by visiting www.Northwell.ethicspoint.com online or by scanning the QR code.