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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 problems caused by medicines.
• 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 caused by parasites.
• Lactose intolerance
• Norovirus infection
• Medicines, such as antacids containing magnesium and some cancer treatments
• Rotavirus or infections caused by other viruses.
• Salmonella infection or other infections that may be caused by bacteria.
• Shigella infection
• Stomach surgery
• Traveler's diarrhea

Chronic diarrhea causes may include:

• Celiac disease
• Colon cancer — cancer that starts in the part of the large intestine called the colon.
• Crohn's disease — which causes tissues in the digestive tract to become inflamed.
• Inflammatory bowel disease (IBD)
• Irritable bowel syndrome — a group of symptoms that affect the stomach and intestines.
• Medications used to treat heartburn, such as proton pump inhibitors and H-2 receptor antagonists
• Radiation therapy
• Small intestinal bacterial overgrowth (SIBO)
• Ulcerative colitis — a disease that causes ulcers and swelling called inflammation in the lining of the large intestine.
• 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 go away 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 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).