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.

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
• Norovirus infection
• Medicines, such as antacids containing magnesium and some cancer treatments
• Rotavirus
• 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
• Inflammatory bowel disease (IBD)
• Irritable bowel syndrome
• 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 type of inflammatory bowel disease)
• Whipple's disease

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

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).