Common causes of gas and bloating include: 1  Swallowed air. 2  If swallowed air is not burped up, it passes through the digestive tract and is released through the anus as flatus. 3  Excessive air swallowing may cause hiccups. 4  Foods and beverages.5  The amount of gas that different foods cause varies from person to person.ommon causes of gas and bloating include: 1  Swallowed air. 2  If swallowed air is not burped up, it passes through the digestive tract and is released through the anus as flatus. 3  Excessive air swallowing may cause hiccups. 4  Foods and beverages.