what causes indigestion and gas
1 heartburn or acid indigestion (acid reflux), 2  bloating, 3  gas, 4  nausea, 5  acidic taste in the mouth, 6  stomach discomfort, 7  constipation or diarrhea, and. 8  decreased appetite. 9  Indigestion has many causes including medical conditions, medications, diet, and lifestyle.