Intestinal gas is normally present from the stomach to the rectum. We notice intestinal gas only if it is excessive or causing pain. Most people burp occasionally and people pass gas rectally several times a day which is normal. Excessive passage of gas from the mouth or from rectum can indicate a digestive disorder.
Some people swallow air while eating, drinking or chewing gum which can cause excessive burping.. colonic gas is formed as some food is metabolized by the bacteria in the colon. Dairy products, beans, lentils and some digestive disorders can cause excessive colonic gas.