Gaviscon original was the first remedy of its kind available in the uk it contains sodium alginate which is derived from seaweed and is classed as an 39alginate39 which means that it forms a 39raft39 in the stomach which helps prevents acid coming back up into the oesophagus food pipe as such it is effective at treating the classic symptoms of heartburn a burning pain in the chest and mild acid regurgitation gaviscon original has a soothing effect lasting for up to four hou