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Diarrhea

Medically reviewed by Drugs.com. Last updated on Jul 14, 2021.

Definition

Everyone occasionally has diarrhea — loose, watery and more-frequent bowel movements. You might also have abdominal cramps and produce a greater volume of stool. The duration of diarrhea symptoms can provide a clue to the underlying cause.

Acute diarrhea lasts from 2 days to 2 weeks. Persistent diarrhea lasts 2 to 4 weeks. Acute and persistent diarrhea are typically caused by a bacterial, viral or parasitic infection of some sort.

Chronic diarrhea lasts longer than does acute or persistent diarrhea, generally more than four weeks. Chronic diarrhea can indicate a serious disorder, such as ulcerative colitis or Crohn's disease, or a less serious condition, such as irritable bowel syndrome.

Causes

Acute or persistent diarrhea causes may include:

  • Antibiotic-associated diarrhea (or other medication side effects)
  • Artificial sweeteners
  • C. difficile infection
  • Coronavirus disease 2019 (COVID-19)
  • Cryptosporidium infection
  • Cytomegalovirus (CMV) infection
  • E. coli
  • Food intolerances
  • Food poisoning
  • Fructose intolerance
  • Giardia infection (giardiasis) (or other infections causes by parasites)
  • Lactose intolerance
  • Medicines, such as antacids containing magnesium and some cancer treatments
  • Norovirus infection
  • Rotavirus (or infections caused by other viruses)
  • Salmonella infection (or other infections that may occur from bacteria)
  • Shigella infection
  • Stomach surgery
  • Traveler's diarrhea

Chronic diarrhea causes may include:

  • Celiac disease
  • Colon cancer
  • Crohn's disease (a type of inflammatory bowel disease)
  • Inflammatory bowel disease (IBD)
  • Irritable bowel syndrome
  • Medications used to treat heartburn, such as proton pump inhibitors and H2 receptor antagonists
  • Radiation therapy
  • Small intestinal bacterial overgrowth (SIBO)
  • Ulcerative colitis
  • Whipple's disease

Some infections, such as giardia or C. difficile infection, may lead to chronic diarrhea if not treated.

When to see a doctor

Most cases of acute diarrhea resolve without treatment. However, severe diarrhea (greater than 10 bowel movements a day or diarrhea where fluid losses are significantly greater than oral intake) can cause dehydration, which can be life-threatening if untreated. Dehydration is particularly dangerous in children, older adults and those with weakened immune systems.

Seek medical attention for a child with these signs and symptoms:

  • Diarrhea that doesn't improve after 24 hours
  • No wet diaper in three or more hours
  • A fever of more than 102 F (39 C)
  • Bloody or black stools
  • A dry mouth or tongue or cries without tears
  • Unusually sleepy, drowsy, unresponsive or irritable
  • A sunken appearance to the abdomen, eyes or cheeks
  • Skin that doesn't flatten if pinched and released

Schedule a doctor's visit for an adult with these symptoms:

  • Diarrhea lasts more than two days without improvement
  • Excessive thirst, dry mouth or skin, little or no urination, severe weakness, dizziness or lightheadedness, or dark-colored urine, which could indicate dehydration
  • Severe abdominal or rectal pain
  • Bloody or black stools
  • A fever of more than 102 F (39 C)

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