Gaviscon Double Action Liquid is for the effective relief of pain and discomfort of heartburn and acid indigestion. Gaviscon Double Action Mint Liquid bring fast, soothing and long lasting relief for up to 4 hours from heartburn and indigestion. It work in two different ways: Neutralising excess stomach acid to help relieve discomfort. Forming a protective barrier over the stomach contents to help soothe burning sensation in your chest.