What are the common causes of chronic diarrhea in adults?

Chronic diarrhea in adults can result from many underlying conditions. The most common causes include infections, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), celiac disease, lactose intolerance, and side effects of certain medications like antibiotics. Hormonal problems such as hyperthyroidism or diabetes complications may also play a role. In rare cases, cancers of the digestive system can cause persistent diarrhea. Identifying the exact cause is important for effective treatment, so adults with ongoing symptoms should consult a doctor for proper evaluation.