Get relief from heartburn and its associated symptoms with the Extra-Strength Antacid Chews from up & up™ Each extra-strength antacid tablet is formulated with calcium carbonate that helps quickly relieve your heartburn, acid ingestion and sour stomach. Featuring a delightful mix of fruit flavors, these calcium carbonate antacid tablets are easy to chew and help get you back to feeling your best.100% Satisfaction Guaranteed.