Intestinal gas is a mix of odorless vapors, including carbon dioxide, oxygen, hydrogen, nitrogen, and methane. These gasses form in the digestive system. Unpleasant sulfur odor develops when these vapors mix with intestinal bacteria.
Your body releases gas through the mouth by belching or rectum (flatulence). Sometimes gas gets trapped in the stomach. This gas build up can lead to abdominal pain and bloating (a swollen or tight feeling.
Intestinal gas is quite common as it is a fact of life, a natural result of food digestion. Everyone feels gassy at different times. According to studies, most people pass gas (fart) up to 21 times per day.