Dysphagia refers to difficulty swallowing. Problems swallowing can be caused by eating too fast or not chewing food well enough before swallowing, and are usually not a cause for concern. Chronic dysphagia can be a symptom of a serious medical condition, such as esophageal cancer, which requires immediate medical treatment.

Deglutition (swallowing) is an important component of digestion. Swallowing is a complex process that involves coordinated action by muscles and nerves. When a person swallows food or liquid bolus (soft mass of chewed food), the tongue pushes it to the back of the throat (pharynx). Muscle contractions quickly move the bolus through the pharynx. Then, it moves past the trachea (windpipe) and into the esophagus. The part of the process that occurs in the mouth is voluntary. The movement of food from the throat to the esophagus is involuntary.

Sphincters at the top and bottom of the esophagus open each time a person swallows to let the bolus pass, then quickly close. Muscles in the esophageal wall help propel the bolus toward the stomach during a coordinated process called peristalsis. The lower esophageal sphincter (LES) allows the bolus to enter the stomach and prevents stomach acid from backing up (refluxing) into the esophagus.

Swallowing becomes difficult when food does not pass normally from the mouth to the stomach. This difficulty may be temporary and disappear on its own. For instance, eating too fast or taking bites that are too big may make swallowing difficult. Other times, dysphagia may be caused by an underlying condition or disorder (e.g., esophageal ulcer, gastroesophageal reflux disease).

Prolonged dysphagia can interfere with digestion and prevent important fluids and nutrients from being absorbed by the body. Therefore, patients with chronic dysphagia are at risk for dehydration and malnutrition.