Everyone has gas in the digestive tract, and most people pass this gas either via the rectum or the mouth. As a matter of fact, the average person passes gas about 12 to 14 times a day. When there is excessive gas, however, you can experience discomfort - even pain. This is called “having gas”.
Gas in the body is comprised of different vapors - most of them practically odorless. Common gasses found in the body are oxygen, carbon dioxide, nitrogen, and hydrogen. When the gas passes through the rectum, it can take on an unpleasant smell due to the bacteria found in the large intestine. This bacteria releases tiny amounts of sulfur, which can smell like rotten eggs.
The cause of gas is two-fold: when you swallow air and when undigested food break down. Most of the swallowed air is released via burping. People who smoke, eat and drink quickly, and chew gum may experience gas due to this reason. In some cases, food is not digested properly due to different reasons. When this happens, more gas is produced. This gas eventually passes out as flatulence. Certain kinds of food cause gas more than others - carbohydrates, for example. Also, some food items may cause gas in some individuals but may not affect others in the same way.
If you experience gas pain, you may want to observe what food items trigger it. Eliminating or lessening the intake of these items will help you deal with the problem. If the problem persists, then you have to see a doctor, as there may be an underlying cause.