The esophagus is a hollow, multi-layered muscular tube-shaped organ, connecting the pharynx to the stomach. Its function is regulated by complex neural mechanisms responsible for swallowing and clearance of gastroesophageal refluxate, in order to ensure airway protection and efficient bolus propulsion. Gastroesophageal reflux disease (GERD) is defined as troublesome symptoms and/or complications caused by the reflux of gastric contents. GERD is frequent and the prevalence varies globally, with risk factors including obesity and smoking. Its pathophysiology involves the presence of hiatal hernia, ineffective esophageal motility and visceral hypersensitivity. Achalasia is a rare disorder marked by impaired relaxation of the lower esophageal sphincter and absent or spastic contractions of the esophageal body. It is characterized by progressive degeneration of esophageal myenteric neurons in genetically predisposed individuals leading to loss of inhibitory nerve function. Hypercontractile esophagus (HE) is a rare disorder characterized by an excessive peristaltic vigor of the esophageal body caused by altered excitatory cholinergic activity within the myenteric plexus. It may be associated with esophagogastric junction outflow obstruction. Both achalasia and HE are associated with dysphagia and chest pain and can be induced by chronic use of opioid analgesics.