Chronic diarrhea is defined as the passage of more than 200 g of stool per day for more than three weeks. This condition may result from decreased absorption of gastrointestinal contents or increased fluid secretion into the bowel. Although chronic diarrhea can have many etiologies, irritable bowel syndrome, lactose intolerance, dietary factors, inflammatory bowel disease and colon cancer are the causes most frequently encountered in primary care practice. An orderly work-up, beginning with a complete history an a thorough physical examination, is essential. Whenever possible, treatment should be directed at the underlying cause of the diarrheal condition. If the diarrhea persists and the etiology remains obscure, administration of opiates or bile-sequestering agents often is helpful in alleviating symptoms. New approaches to decreasing secretions, such as the use of clonidine therapy, are being studied.