Hi, Thanks for posting in HCM. I understand your concern. Mylanta suspension contains aluminum, magnesium and simethicone as ingredients. Mylanta suspension is an antacid and antiflatulent. It is used for treating acid indigestion, heartburn, gas, and sour stomach. Most common side effects encountered with its use include nausea, constipation, diarrhea, or headache. Since you are experiencing acidity despite taking Mylanta, it would be advisable for you to take proton-pump inhibitor medication such as Rabeprazole once a day on empty stomach. Hope the information provided would be helpful. All the best.