Belching refers to the action of releasing gases from the alimentary canal mainly from the esophagus and the stomach via the mouth. In most cases the action produces a sound and an unpleasant odor. It is also called burping or eructation. The cause of the action is the intake of air during eating or drinking and it is this gas that is expelled through burping. The gas that comes out when a person belches is majorly made of a mixture of nitrogen and oxygen.
Intake of carbonated drinks such as champagne, soft drinks, energy drinks and beer can also induce belching in which case the gas expelled is largely carbon dioxide. There are also drugs especially the diabetes drugs like Byetta and metformin which do cause belching and this is particularly so when they are taken in large doses. In this circumstance however the belching is temporary and after a few weeks, the problem usually disappears.
Belching becomes a cause for alarm when it comes along with other symptoms like nausea, heart burn and dyspepsia in which case the belching may be a sign of an ulcer or hernia. Other reasons for belching are gastritis, food allergy, acid reflux condition, problems of the gall bladder, H. pylori etc,
The sound that accompanies belching is the result of the vibrations in the sphincter found in the upper end of the esophagus as the gas comes out. Belching is also a prevalent phenomenon in regions with very low gravity. In such areas, the food and gases in the stomach tends to float near the sphincter that opens into the stomach. This tends to stimulate belching and the contents of the stomach can be concurrently spewed out. Belching in children is very common because the infants have the tendency to accumulate a lot of gases in the stomach. This causes a lot of discomfort to the child.