How Does Gaviscon Double Action Liquid Work Gaviscon's active ingredients contain sodium alginate, sodium bicarbonate & calcium carbonate. Gaviscon Double Action Liquid Peppermint helps to neutralise the excess stomach acid while forming a barrier over the stomach contents that prevents the acid escaping up into the chest & food-pipe, relieving the painful burning sensation. How To Take Gaviscon Double Action Liquid Peppermint Adults & children over 12: 10-20ml (2 to 4ml spoonful's) to be taken after meals & at bedtime, up to four times a day. Not recommended for children under 12 years old except on a doctor's advice. If after 7 days, no relief is found, speak to your doctor. Exceeding the recommended dose may cause bloating, this is not likely to be harmful but contact your doctor or pharmacist. If on a restricted diet, contact your doctor before taking this medicine.