Inclusion Criteria:  Patients of both sexes over 18 years of age Patients with gastroesophageal reflux disease and heartburn (more than 3 weekly episodes of heartburn for at least 4 consecutive weeks) not related to medication intake Patients not on proton pump blockers or H2-receptor antagonists Patients able to understand the study implications and who sign the informed consent.  Exclusion Criteria:  Pregnant or nursing women Patients who are currently using or have used other medications or antacid products for the treatment of reflux and hyperacidity symptoms within 7 days prior to enrolment in this study. Patients treated with antihypertensive drugs, calcium channel blockers or non-steroidal anti-inflammatory drugs (NSAIDs) Patients with hypercalcaemia, hypertension, renal failure or other conditions in which the use of the components of the investigational product is not recommended. Patients with serious diseases that, in the physician's opinion, could interfere with the results of the study or prevent their participation in it.