TUMS is an antacid made of calcium carbonate. It is available over-the-counter at many retail stores, including drug stores, grocery stores and mass merchandisers. It provides relief from acid indigestion, heartburn and sour stomach. It is also an excellent source of calcium.We're about to pull a deliciously smooth move to get rid of that heartburn. TUMS Extra Strength Smoothies Berry Fusion, 140 count, are delicious, finely textured chewable tablets. They provide fast heartburn relief which is why TUMS is the #1 selling antacid tablet in Canada. Each Smoothie contains more acid-neutralizing power than that of regular strength TUMS, providing you with fast relief for your heartburn, acid indigestion, and sour stomach caused by excess stomach acidity.