Achalasia is a rare disease of the muscle of the esophageal body and the lower esophageal sphincter (LES). LES is a valve made of muscles at the lower end of food pipe (Esophagus) which opens when a person swallows foods and functions to prevent the food from coming back from stomach to esophagus after eating. In Achalsia this valve do not open on swallowing as it should do normally. Also the muscles of the food pipe which contract and send the food down normally do not work properly. Both the things together makes the food to retain in the food pipe for a longer time. Gradually with time if no treatment is done the food pipe enlarges and collects a large amount of food inside. A person can vomit (regurgitate this collected food hours after eating undigested).This food coming back may go to Trachea (airpipe) and Lungs in sleep causing cough and pneumonia. As muscles of foodpipe do not function as it should it is called an esophageal motility (activity of muscle) disorder
