Rennie Peppermint tablets are a natural remedy for heartburn. They contain two antacids, calcium carbonate and magnesium carbonate, which work by neutralising stomach acid and turning it into water and other natural substances. These tablets act directly in the oesophagus and stomach, and are then eliminated by the body. The usual dosage is 1 to 2 tablets initially, taken up to 3-4 times per day. In cases of more frequent or severe pain, the dose may be increased for a short period, up to 12 tablets per day. Rennie Peppermint tablets are intended for adults and children over 12 years, and treatment should not exceed 14 days.