Quote (from the Daily Mail):
"For most, burping is a benign sign of stomach gas - excess swallowed air trapped in our digestive systems.
Burping may be a sign of having eaten foods high in fibre. Excessive burping can also indicate being lactose intolerance.
Lactase is an enzyme that breaks down lactose in the digestive tract. If it's missing, many foods, including milk and other dairy products, can't be digested properly, resulting in gas.
Burping a lot may also signal gallbladder disorders or even stomach or colon cancer.
Other signs of these conditions include bloating, weight loss and vomiting blood.
Excessive burping with severe nausea or vomiting may be danger signs of a heart attack."
Source:
http://www.dailymail.co.uk/health/article-5302 26/Become-diagnostic-detective-The-real-reason s-niggling-symptoms.html
Chris