An over-the-counter antacid is often used to relieve mild cases of heartburn or acid reflux. Though they are available without a doctor’s prescription, they should be taken only under a doctor’s advice. As per American Academy of Family Physicians:

• There are different types of antacids, which work in different ways.
• Always consult your doctor before taking an antacid.
• To manage an ulcer, an antacid may need to be taken along with an antibiotic.
• If one needs more calcium to help strengthen bones, one should take an antacid that contains calcium carbonate.
• Antacids may have minor side effects such as nausea, headache, diarrhea or constipation in some patients.
• Read the label carefully to make sure that one is not allergic to any of the ingredients.
• People with kidney disease may not be able to take all sorts of antacids.
• An antacid may interact with other medications.