Gelusil MPS Original Liquid Sugar Free Mint is used to treat acidity, heartburn, indigestion, gastritis (inflammation of the stomach), and stomach upset. It works by neutralising excess stomach acid and decreasing the surface tension of gas bubbles, thereby facilitating gas expulsion through flatus or belching (burping). It also prevents the accumulation and formation of gas in the digestive tract. In some cases, you may experience certain common side effects such as constipation, loss of appetite, weakness and diarrhoea. Before taking this medicine, you should tell your doctor if you are allergic to any of its components or if you are pregnant/breastfeeding, and about all the medications you are taking and pre-existing medical conditions