Burping or belching is most often caused by swallowed air, usually while eating or drinking. Burping that occurs with other symptoms, such as pain, heartburn, nausea, a decreased appetite, or weight loss, may have a more serious cause.

• Gallstones or another problem with the gallbladder may cause burping that is worse after eating and occurs with pain in the upper right abdomen that spreads to the back or shoulder.
• Gastroesophageal reflux (GERD) may cause burping and heartburn that gets worse when you bend over or lie down.
• An ulcer may cause persistent burping, indigestion, and pain that comes and goes in the upper abdomen.
• Cancer of the stomach or esophagus may cause burping that occurs with nausea, decreased appetite, and persistent abdominal discomfort and fullness after eating.

Other conditions that may cause burping include:

• Anxiety.
• Slowed movement of food through the intestines (motility disorders).
• Blocked passage of food through the stomach or intestines (bowel obstruction or gastric outlet obstruction).
• A large collection of undigested material, such as food, hair, or swallowed objects in the stomach (gastric bezoar).