Most people are familiar with the loose, watery stools of diarrhea. Sudden diarrhea can resolve on its own or with over-the-counter (OTC) medications. It’s generally not a cause for concern.

If you’re experiencing frequent or severe diarrhea, it’s important to replenish fluids to avoid dehydration.

Recurring bouts of diarrhea or chronic diarrhea can have a significant impact on your life. It may also be a sign that you have an underlying condition that should be treated.

Continue reading as we explore some reasons for sudden diarrhea, conditions that can cause chronic diarrhea, and when it’s time to see your doctor.

Sudden or acute diarrhea usually resolves on its own within a few days, even if you never figure out what caused it. The following are some possible causes of a sudden, acute case of diarrhea:

Travelers’ diarrhea

If you’ve ever been told not to drink the water while traveling to certain countries, it’s for a good reason. Some countries with unsanitary conditions can expose you to drinking water or food contaminated with parasites such as:

  • Cryptosporidium
  • Entamoeba histolytica
  • Giardia lamblia

Or bacteria such as:

  • Campylobacter
  • Escherichia coli (E. coli)
  • Salmonella
  • Shigella

Travelers’ diarrhea generally lasts a few days. See your doctor if it lasts longer.

Viral gastroenteritis

Viral gastroenteritis is what many people refer to as the “stomach flu.” But it’s not really influenza and it affects the intestines, not the stomach. Some viruses that cause this are:

  • adenovirus
  • astrovirus
  • cytomegalovirus
  • norovirus
  • Norwalk virus
  • rotavirus
  • viral hepatitis

Viral gastroenteritis can also cause abdominal pain, vomiting, and fever.


Some medications can cause diarrhea. For example, while antibiotics are destroying bad bacteria, they’re also destroying good bacteria. It’s this imbalance that can give you diarrhea. Other medications that can cause diarrhea include:

  • antacids that contain magnesium
  • certain drugs used to treat cancer
  • overuse of laxatives or stool softeners

Diarrhea that doesn’t clear up within four weeks is considered chronic. About 3 to 5 percent of the American population has chronic diarrhea. The following are a few possible causes of chronic diarrhea.


Some of the infections you get from parasites and bacteria don’t go away on their own and require treatment. Following an infection, you might have trouble digesting milk or soy products.

Exocrine pancreatic insufficiency (EPI)

EPI is a condition in which your pancreas can’t make enough enzymes to break down food. EPI makes it hard for your body to absorb nutrients. It can also lead to chronic digestive problems such as frequent diarrhea and:

  • gas, bloating
  • malnutrition
  • oily, foul-smelling stools
  • stomachache
  • unexplained weight loss

Irritable bowel syndrome (IBS)

There are several types of IBS, a functional gastrointestinal disorder. The type that causes diarrhea is called IBS-D.

If you have IBS-D, you may have normal bowel movements on some days and abnormal movements on others. On abnormal days, your movements are more loose or watery than hard or lumpy. Other symptoms may include:

  • abdominal discomfort
  • bloating
  • mucus in the stool

Other names for IBS include spastic colon, spastic bowel, and IBS colitis.

Inflammatory bowel disease (IBD)

IBD is a term that covers Crohn’s disease and ulcerative colitis, both of which cause chronic inflammation of the gastrointestinal (GI) tract. Crohn’s disease can involve any part of the digestive tract. Ulcerative colitis is limited to the colon. Symptoms are similar, though. In addition to chronic diarrhea, you might also have:

  • abdominal pain
  • bloody stools
  • weight loss
  • endocrine disorders

Chronic diarrhea can also be a symptom of endocrine disorders such as:

  • Addison’s disease
  • carcinoid tumors
  • gastrinoma, or Zollinger-Ellison syndrome
  • surgery

Chronic diarrhea can sometimes be the result of abdominal surgery involving your:

  • appendix
  • gallbladder
  • intestines
  • liver
  • pancreas
  • spleen
  • stomach

Sensitivities or allergies to foods such as soy, eggs, or seafood can cause diarrhea. Some others are:

  • Lactose. People who are lactose intolerant may have diarrhea after eating milk and other dairy products.
  • Fructose and high-fructose corn syrup. If you’re fructose intolerant, you might have diarrhea after eating foods or soft drinks that contain fruits or honey.
  • Artificial sweeteners. Sugar alcohols typically added to sugar-free products can trigger diarrhea. These include sorbitol, mannitol, and xylitol.
  • Gluten. If you have celiac disease or a gluten intolerance, your body is sensitive to gluten, which can be found in foods that contain wheat flour.

Too much alcohol or caffeinated beverages like coffee can also cause diarrhea.

Experiencing diarrhea from time to time isn’t pleasant, but it isn’t cause for concern, either. However, if your symptoms are serious enough that you have to stay home or take time off work, it may be time to see a doctor.

If your diarrhea is the result of an underlying condition, the sooner you’re able to get a diagnosis and start on treatment, the better. See your doctor if you have severe diarrhea accompanied by:

  • fever of 102°F (38.9°C) or higher
  • vomiting
  • abdominal or rectal pain
  • stools that contain blood or pus
  • symptoms of dehydration like confusion, dark urine, dizziness, extreme thirst
  • weight loss

If you frequently experience diarrhea, or it’s become chronic, it’s important to get a diagnosis. Be sure to tell your doctor about all your symptoms, how frequently they occur, and how long they last. Also, be sure to talk about any known medical conditions or if you have a family history of GI diseases.

If no cause can be found upon initial examination, your doctor may refer you to a gastroenterologist for further diagnostic testing. GI disorders can be treated and managed.