Most people believe that their Acid Reflux (Heartburn) is caused by having too much stomach acid, but heartburn can actually be caused from too little of it. Scientific literature says that heartburn and GERD (Gastroesophageal Reflux Disease, aka Acid Reflux) are not considered to be diseases of excess stomach acid. Experts now know that Acid Reflux can be caused when not enough stomach acid is present and excess gas forces the lower oesophageal valve (LES) to open and allows acid to hit your throat.