Diarrhea is caused by a variety of factors that interfere with the normal absorption of water and nutrients in the intestines, leading to loose or watery stools. Common causes include:
- Infections: Viral infections (such as norovirus and rotavirus), bacterial infections (like Salmonella, E. coli, Campylobacter), and parasites (such as Giardia and Cryptosporidium) are frequent causes, often resulting from contaminated food or water
- Food-related causes: Food intolerances (e.g., lactose intolerance), food allergies (such as celiac disease), and eating foods that upset the digestive system can trigger diarrhea
- Medications: Antibiotics, laxatives, magnesium-containing antacids, chemotherapy drugs, and some other medicines can cause diarrhea as a side effect
- Digestive diseases: Chronic conditions like inflammatory bowel diseases (Crohn’s disease, ulcerative colitis), irritable bowel syndrome (IBS), bile acid malabsorption, and celiac disease can lead to diarrhea
- Other causes: Surgery on the stomach or gallbladder, metabolic conditions such as hyperthyroidism, certain cancers, and radiation treatments may also cause diarrhea
- Functional disorders: Problems with how the gut and brain interact, such as IBS or functional diarrhea, can cause chronic diarrhea without an underlying disease
In summary, diarrhea results when the intestines fail to properly absorb water or secrete excess fluid, often due to infections, food issues, medications, or chronic intestinal conditions
