Heartburn usually doesn't pose a serious threat to your health. However, complications can occur with severe, frequent, and persistent acid reflux. If you have severe heartburn or heartburn two or more times a week, you may have a condition called GERD (gastroesophageal reflux disease) and you should see your doctor. Without treatment, chronic GERD can cause inflammation, ulcers, and scarring. GERD can also lead to changes in the cells lining the esophagus. Known as Barrett's esophagus (shown here), these changes raise the risk of esophageal cancer.