Gaviscon Advance Chewable Tablets Peppermint Flavour is an extra strength formula that works instantly to bring soothing relief from the pain of heartburn, indigestion, and reflux cough. These tablets are suitable to take during pregnancy. How it works? Gaviscon Advance contains double the concentration of sodium alginate and forms a stronger, resilient raft over the stomach to prevent acid coming back up into the food pipe.