Sudden watery diarrhea isn’t always serious. Causes can include medications. It is generally not a cause for concern, but if it recurs, it may require more significant treatment.

Most people are familiar with the loose, watery stools of diarrhea. Typically it resolves on its own or with the us of over-the-counter (OTC) medications.

But recurring bouts of diarrhea or chronic diarrhea can impact your life significantly. Frequent episodes may also be a sign that you have an underlying condition that needs treatment.

Continue reading as we explore some reasons for sudden diarrhea, conditions that can cause chronic diarrhea, and when it’s time to contact a doctor or other healthcare professional.

Sudden diarrhea usually resolves on its own within a few days, even if you never find the cause. The following are some possible causes of a sudden, or acute, case of diarrhea:

  • traveler’s diarrhea
  • viral gastroenteritis
  • medications

Traveler’s diarrhea

If while traveling you’ve ever been told not to drink the water, it’s for a good reason. You could be exposed to harmful drinking water or food in some countries.

The water or food may contain parasites such as:

  • Cryptosporidium
  • Entamoeba histolytica
  • Giardia

They may also contain bacteria such as:

  • Campylobacter
  • E. coli
  • Salmonella
  • Shigella

Traveler’s diarrhea generally lasts a few days. Contact a healthcare professional if it lasts longer.

Viral gastroenteritis

Viral gastroenteritis is what many people refer to as the “stomach flu.” Despite its name, it’s not influenza, and it affects the intestines, not the stomach.

Some viruses that cause viral gastroenteritis include:

  • adenovirus
  • astrovirus
  • cytomegalovirus (CMV)
  • norovirus
  • rotavirus
  • viral hepatitis

Viral gastroenteritis can also result in:

  • abdominal pain
  • vomiting
  • fever


Some medications can cause diarrhea.

For example, while antibiotics are destroying bad bacteria, they’re also destroying good bacteria. This creates an imbalance that can cause diarrhea.

Other medications that can cause diarrhea include:

  • antacids that contain magnesium
  • certain drugs used to treat cancer
  • laxatives or stool softeners when overused

Diarrhea that doesn’t clear up within 4 weeks is considered chronic.

There are many possible causes of chronic diarrhea, including:

  • infection
  • exocrine pancreatic insufficiency (EPI)
  • celiac disease
  • irritable bowel syndrome (IBS)
  • Inflammatory bowel disease (IBD)

About 5% of the population has chronic diarrhea.


Some parasitic and bacterial infections don’t go away on their own and require treatment. Following an infection, you might have trouble digesting milk or soy products, leading to diarrhea.

Exocrine pancreatic insufficiency (EPI)

Exocrine pancreatic insufficiency (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
  • stomachache
  • oily, foul-smelling stools
  • unexplained weight loss
  • malnutrition

Celiac disease

Celiac disease is an autoimmune disorder that affects the way your body processes gluten. Your body attacks gluten proteins, resulting in damage to the small intestine.

Celiac disease causes symptoms such as:

  • stomach discomfort
  • bloating
  • unintentional weight loss
  • rashes

In some cases, celiac disease may cause constipation instead of chronic diarrhea.

Irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder, which means the GI tract doesn’t work as it should. Other names for IBS include:

  • spastic colon
  • spastic bowel
  • IBS colitis

There are several types of IBS. The type that primarily causes diarrhea is called IBS-D.

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

IBS-mixed (IBS-M) can cause chronic diarrhea as well. This type is also known as IBS-alternating (IBS-A) because it causes both diarrhea and constipation over time.

Other symptoms of IBS may include:

  • abdominal discomfort
  • bloating
  • mucus in the stool

Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is an umbrella term for conditions such as Crohn’s disease and ulcerative colitis, both of which cause chronic inflammation of the 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:

  • nocturnal diarrhea, or diarrhea at night
  • bloody stools
  • abdominal pain
  • weight loss
  • endocrine disorders

Microscopic colitis is a less common type of IBD. It involves inflammation of the colon.

Chronic diarrhea is the primary symptom, but it can also cause:

  • nocturnal diarrhea
  • abdominal pain
  • fatigue

People diagnosed with microscopic colitis tend to be older than people diagnosed with Crohn’s disease or ulcerative colitis.

Other possible causes

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

  • Addison’s disease, in which your body doesn’t make enough of the hormones cortisol or aldosterone
  • carcinoid tumors
  • Zollinger-Ellison syndrome, which causes tumors in the pancreas or small intestine

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

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

Sensitivities or allergies to products such as soy, eggs, or seafood can cause diarrhea. Other food triggers include:

  • Lactose: People who are lactose intolerant may have diarrhea after consuming milk and other dairy products.
  • Fructose and high fructose corn syrup: If you’re fructose intolerant, you might have diarrhea after consuming foods or soft drinks that contain fruits or honey.
  • Artificial sweeteners: The sugar alcohols typically added to sugar-free products can trigger diarrhea. These include sorbitol, mannitol, and xylitol.
  • Gluten: If you have celiac disease or another gluten-related disorder, your body is sensitive to the protein gluten. Gluten is found in foods that contain certain grains, such as wheat or rye.

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

Experiencing diarrhea from time to time isn’t pleasant, but it’s not cause for concern either.

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

But if your symptoms are serious enough that you have to stay home or take time off from work, it may be time to contact a doctor or other healthcare professional. 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.

Seek medical attention 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
  • weight loss
  • symptoms of dehydration, such as:
    • confusion
    • dark urine
    • dizziness
    • extreme thirst

If you frequently experience diarrhea or it’s become chronic, it’s important to get a diagnosis.

Be sure to tell a doctor or other healthcare professional about all of 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 disorders.

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