What Causes Diarrhea?

From the WebMD Archives

Diarrhea is inconvenient, unpleasant, and happens to nearly everyone. Of all reported illnesses in the U.S., diarrhea is the second most common. The average adult has diarrhea four times a year. American children typically have seven to 15 cases of diarrhea by the time they reach age five.

Everyday things such as food, medication, or stress can cause diarrhea. However, diarrhea sometimes may signal an underlying medical condition. If diarrhea keeps you running for the toilet, read on to learn about some common triggers and how you can cope.

Bacterial Causes of Diarrhea

Bacteria are part of everyday life, and normally bacteria and humans live together peacefully. However, some bacteria can wreak havoc on your digestive well-being. These tiny bugs find fertile breeding ground in raw meats, eggs, shellfish, and unpasteurized milk.

Cases of food contamination causing diarrhea are rare in the U.S., says Alexander Rapisarda, MD, a specialist in gastroenterology and hepatology at Robert Wood Johnson University Hospital in East Brunswick, N.J. He tells WebMD, “The most common food-related cases of diarrhea come from food that was not refrigerated well enough or went bad before the patient ate it.”

To reduce your risk of bacteria-related diarrhea, cook meat, poultry, and eggs completely. Wash your hands, utensils, and surfaces. Refrigerate leftovers quickly, don’t leave them at room temperature longer than necessary.

When deciding where to dine out, look for health department ratings online or posted in the restaurant. These ratings indicate the restaurant kitchen’s levels of cleanliness and food safety.

Viral Causes of Diarrhea

Some viral infections can lead to diarrhea and vomiting. These viral strains are highly contagious, traveling easily from unwashed hand to unwashed hand. Shared drinks, utensils, and contaminated food also provide passage into your unsuspecting stomach. People who no longer have symptoms or never exhibited symptoms in the first place can sometimes spread these viruses.

Just like with bacteria, hand washing, clean kitchens, and common sense go a long way to keep viruses under wraps. If you or someone you know has diarrhea, do not eat or drink from the same containers. You might never know for sure if a bacteria or virus caused your diarrhea — the symptoms and incubation periods are often the same. In either case, the diarrhea and stomach upset usually work their way out of your system within two to three days.


Traveler’s Diarrhea

Delhi Belly and Montezuma’s Revenge are two nicknames for an experience shared by many unhappy travelers. Depending on the country, between 30% and 70% of travelers suffer a bout of diarrhea and vomiting, courtesy of contaminated local foods or water. If you travel to a developing country, avoid raw, unpeeled produce and water from the faucet. Eat only cooked foods prepared in a clean kitchen and stick with bottled water, even to brush your teeth. Typically, traveler’s diarrhea works its way out of your system within 12 hours.

Chronic Diarrhea

Sometimes diarrhea does not go away of its own accord. Chronic diarrhea has many possible causes, including some medications or intolerance to certain foods. Persistent and repeated bouts of diarrhea can also be a sign of a serious underlying condition.

1. Diarrhea caused by medication

Sometimes good medicines lead to bad diarrhea. “As more patients are treated with antibiotics, we see more cases of Clostridium difficile colitis,” Rapisarda tells WebMD. While going after bad bacteria, antibiotics can also kill good bacteria that protect your intestines. “Ironically, antibiotics to treat one type of infection can make a patient more vulnerable to this other type of infection.”

Blood pressure medications, cancer drugs, and antacids can also trigger diarrhea. If you take any of these medications and experience frequent or ongoing diarrhea, let your doctor know.

2. Diarrhea caused by food intolerance

Diarrhea may be the result if your body has trouble digesting certain foods. Diarrhea-inducing fare includes dairy products and artificial sweeteners. The undigested food causes nausea, diarrhea, cramping, and gas, normally within 30 minutes to two hours of entering your system.

Lactose intolerance affects 30 million to 50 million Americans, most of whom are black, Hispanic, American Indian, or Asian American. The impact of lactose intolerance varies. Some people can drink small amounts of milk in tea or coffee without stomach upset. Some can eat cheese or yogurt, which have less lactose than milk. Note the type and amount of dairy products you eat and their effect. You can also talk to your doctor about dietary supplements that may improve your digestion of dairy products.


3. Diarrhea caused by chronic conditions

Diarrhea that doesn’t go away might be letting you know you have an untreated medical condition. If diarrhea lasts longer than three days, ask your doctor of you might have any of these diarrhea-causing conditions:

Coping With Diarrhea

  1. Rehydrate. Water replaces fluid but not electrolytes lost through diarrhea. Electrolytes are minerals that help your body manage its fluid levels, muscle activity, and other important functions. Go for soup and broth with sodium, fruit drinks or a rehydration fluid such as Ceralyte, Oralyte, or Pedialyte. The Centers for Disease Control and Prevention advise against using sports drinks to rehydrate after a bout of diarrhea.
  2. Eat bland, safe foods. When you have diarrhea, stick with soup and broth. When you feel ready, add lean meat, yogurt, fruits, vegetables, and complex carbohydrates such as rice, potatoes, and bread.
  3. Avoid food triggers. To put an end to diarrhea, steer clear of foods and drinks containing caffeine and lots of sugar, as well as sugar substitutes and fried or fatty foods. Also take a break from high-fiber foods, spicy foods, dairy products, and foods known to cause gas, such as beans, broccoli, and cabbage.
  4. Wash your hands. When you have diarrhea, wash even more often than normal, especially after going to the bathroom and before eating. Don’t bequeath your discomfort to family and friends -- have someone else prepare meals, or order out.

Many things can cause diarrhea, from environmental factors to chronic conditions. Pay attention to your symptoms and be sure to keep yourself hydrated and nourished until the diarrhea clears up. If the problem continues longer than two days, seek medical attention.

WebMD Feature Reviewed by Louise Chang, MD on September 10, 2011



National Digestive Diseases Information Clearinghouse: “Digestive Diseases: Diarrhea.”

CDC: “Foodborne Illness.”

Alexander Rapisarda, MD; specialist in gastroenterology and hepatology, Robert Wood Johnson University Hospital, East Brunswick, N.J.

CDC: “Traveler’s Diarrhea.”

National Digestive Diseases Information Clearinghouse: “Viral Gastroenteritis.”

FDA: “Problem Digesting Dairy Products?”

Mayo Clinic: “Diarrhea.”

UPMC Health A to Z: “Diarrhea.”

MedlinePlus: “Electrolytes.”

The American College of Gastroenterology: “Diarrheal Diseases.”

Dziwe, N. Emergency Medicine News, January 2004; vol 26: p 27.

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