Acute or persistent diarrhea causes may include:

1. Antibiotic-associated diarrhea or other problems caused by medicines.
2. Artificial sweeteners
3. C. difficile infection
4. Coronavirus disease 2019 (COVID-19)
5. Cryptosporidium infection
6. Cytomegalovirus (CMV) infection
7. E. coli
8. Food intolerances
9. Food poisoning (foodborne illness)
10. Fructose intolerance
11. Giardia infection (giardiasis) or other infections caused by parasites.
12. Lactose intolerance
13. Norovirus infection
14. Medicines, such as antacids containing magnesium and some cancer treatments
15. Rotavirus or infections caused by other viruses.
16. Salmonella infection or other infections that may be caused by bacteria.
17. Shigella infection
18. Stomach surgery
19. Traveler's diarrhea

Chronic diarrhea causes may include:

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

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