The path to digestion begins in the esophagus, a long hollow tube that connects the mouth with the stomach. Esophageal irritation manifests as regurgitation. Regurgitation occurs when swallowed food is expelled back out the mouth or nasal passages before entering the stomach. The most common cause of regurgitation is choke, an obstruction within the esophagus caused by a foreign object or poorly chewed food. Choke requires immediate veterinary attention to avoid complications (e.g.: infection, rupture). Other causes of esophageal inflammation include: strictures, tumors, and megaesophagus (enlarged, dilated esophagus).