Peptac is used to treat heartburn, upset stomach characterised by stomach pain and burning, nausea and excess gas. Peptac Aniseed Liquid contains 3 active ingredients that work together to relieve the symptoms of gastro-oesophageal reflux. This occurs when stomach acid flows into the food pipe, which can be caused by many different factors and the most common is just after eating. Reflux symptoms can include painful heartburn, indigestion or acid regurgitation. The active ingredients include sodium alginate, sodium bicarbonate and calcium carbonate and they work together by preventing the acid from flowing back into the foo pipe, but they are not absorbed into the bloodstream. Their effects last for about 3-4 hours on top of the stomach contents and are then broken down in the digestive system.