About Magaldrate Chemical complex of aluminum and magnesium hydroxides, Antacid. Mechanism of Action of Magaldrate This neutralizes the gastric acid and increases the gastric pH. This reduces the direct acid irritant effect. It also enhances mucosal barrier integrity and improves gastroesophageal sphincter tone. Indications for Magaldrate 1. Peptic ulcer 2. Gastritis 3. Reflux oesophagitis 4. Gastric hyperacidity