This article describes changes in the basic digestive functions (motility, secretion, intraluminal digestion, absorption) that occur during aging. Elderly individuals frequently have oropharyngeal muscle dysmotility and altered swallowing of food. Reductions in esophageal peristalsis and lower esophageal sphincter (LES) pressures are also more common in the aged and may cause gastroesophageal reflux. Gastric motility and emptying and small bowel motility are generally normal in elderly subjects, although delayed motility and gastric emptying have been reported in some cases. The propulsive motility of the colon is also decreased, and this alteration is associated with neurological and endocrine-paracrine changes in the colonic wall. Decreased gastric secretions (acid, pepsin) and impairment of the mucous-bicarbonate barrier are frequently described in the elderly and may lead to gastric ulcer. Exocrine pancreatic secretion is often decreased, as is the bile salt content of bile. These changes represent the underlying mechanisms of symptomatic gastrointestinal dysfunctions in the elderly, such as dysphagia, gastroesophageal reflux disease, primary dyspepsia, irritable bowel syndrome, primary constipation, maldigestion, and reduced absorption of nutrients. Therapeutic management of these conditions is also described. The authors also review the gastrointestinal diseases that are more common in the elderly, such as atrophic gastritis, gastric ulcer, colon diverticulosis, malignant tumors, gallstones, chronic hepatitis, liver cirrhosis, Hepato Cellular Carcinoma (HCC), and chronic pancreatitis.