Can you take omeprazole and gaviscon together?

Yes! Although they are both used to reduce the symptoms of reflux ("heartburn"), they work in different ways. Ranitidine (brand name = Zantac) reduces the amount of acid secreted by the stomach lining. Gaviscon contains a mild antacid but its main action is to form a "raft" which floats on top of the stomach contents and makes it less likely to reflux into the oesophagus.