Sudden diarrhea can be acute, lasting only a few days, or chronic. Diarrhea that lasts for more than 4 weeks is usually the result of an underlying condition.

Most people are familiar with the loose, watery stools of diarrhea.

Occasional diarrhea typically isn’t a cause for concern. It usually resolves on its own or with the use of over-the-counter (OTC) medications.

Severe or persistent diarrhea could be a sign of an underlying condition that requires treatment.

Sudden diarrhea is often acute and resolves in a few days with or without treatment. You may not even know what caused or triggered this change in stool.

Sudden diarrhea typically results from exposure to certain bacteria, parasites, or viruses. Some medications can also cause diarrhea.

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 regions.

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

Viral gastroenteritis

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

Some viruses that cause gastroenteritis include:

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

In addition to diarrhea, you may also experience:

  • abdominal pain
  • vomiting
  • fever


Some medications can cause diarrhea. Antibiotics, for example, destroy several types of bacteria — good and bad. This can create an imbalance that causes diarrhea.

Other medications that can cause diarrhea include:

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

About 5% of the population experiences chronic diarrhea, or diarrhea that lasts for more than 4 weeks.

Chronic diarrhea is often the result of an underlying condition. Although some causes, such as infection, can be resolved with treatment, most are lifelong and require long-term management.


Some parasitic and bacterial infections will only resolve with treatment.

Following an infection, you might have trouble digesting milk or soy products, leading to diarrhea.

Exocrine pancreatic insufficiency (EPI)

EPI occurs when your pancreas cannot make enough enzymes to break down food. This makes it difficult for your body to absorb the necessary nutrients.

You may also experience other digestive symptoms, including:

  • 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:

  • abdominal discomfort
  • bloating
  • rash
  • unintentional weight loss

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

Irritable bowel syndrome (IBS)

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)

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:

  • diarrhea at night (nocturnal diarrhea)
  • bloody stool
  • abdominal pain
  • unintentional weight loss

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

Although the primary symptom is chronic diarrhea, microscopic colitis 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 sometimes be the result of abdominal surgery involving your:

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

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

  • Addison’s disease, a rare disorder of the adrenal glands
  • carcinoid tumor, a rare type of cancer that usually grows slowly
  • Zollinger-Ellison syndrome, a rare disorder that causes a buildup of gastric acid, resulting in ulcers or tumors

Sensitivities or allergies to products such as soy, eggs, or seafood can cause diarrhea.

Other food triggers include:

  • Lactose: You may have diarrhea after consuming milk and other dairy products.
  • Fructose and high fructose corn syrup: 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.

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. It’s also important to replenish fluids to avoid dehydration.

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
  • unintentional weight loss

You should also seek medical attention if you develop symptoms of dehydration. This includes:

  • confusion
  • dizziness
  • extreme thirst
  • urine that’s darker than usual

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 your symptoms, how frequently they occur, and how long they last.

It’s also important to share your overall medical history, including any preexisting conditions and whether your relatives have a history of GI disorders.

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