Dysphagia is the medical term for difficulty swallowing. When dysphagia is mild, it may cause an individual only to stop eating for a minute or less, but when it is severe, it can prevent an individual from taking in enough calories for adequate nutrition. Dysphagia has many causes. First, there may be physical (anatomical) obstruction to the passage of food. Second, there may be abnormalities in the function of the nerves of the brain, throat, and esophagus whose normal function is necessary to coordinate swallowing. Finally, there also may be abnormalities of the muscles of the throat and esophagus themselves. Depending upon the cause of the dysphagia, the difficulty swallowing can be mild or severe. Some affected individuals may have trouble swallowing both solids and liquids, while others may experience problems only when attempting to swallow solid foods.