difficulty or pain in swallowing, caused by lesions or stricture of the upper digestive tract, obstruction of the upper digestive tract by tumours or foreign bodies, or disturbances in the nervous or muscular control of swallowing. Obstruction of the esophagus is the most common cause of dysphagia. People with dysphagia may experience a sensation that food or liquid is lodged in the upper digestive tract. The cause of dysphagia may be treated with medication or surgery; patients may also benefit from speech therapy.