Tums and Rolaids share an active ingredient: calcium carbonate, according to Rolaids.com and Tums.com. However, Rolaids also uses magnesium hydroxide in its formulation, which is an ingredient that allows it to work more quickly. The downside to its quick-acting capabilities is that it lasts for a shorter amount of time than antacids using only calcium carbonate as an active ingredient, including Tums.
Tums has been a popular heartburn-fighting medication sold over the counter since 1930, according to Tums.com. It is purported to be the top-selling antacid in the United States, and it relies on just calcium carbonate for effective relief of heartburn symptoms.
Rolaids also uses calcium carbonate in its formula, but it also includes magnesium hydroxide, according to Rolaids.com. The two together neutralize acid and provide relief from acid indigestion and sour stomach. Although both Rolaids and Tums are fairly fast acting, neither is seen as a long-term product for treating heartburn, but offer only short-term relief for heartburn symptoms.
Heartburn that does not respond to medication and that persists over time may be indicative of gastroesophageal reflux disease, also known as GERD, notes Rolaids.com. This condition requires evaluation by a medical professional to stave off problems such as esophageal ulcers, pneumonia and asthma, among others.