Sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide are antacids and they work by neutralising the excess hydrochloric acid present in the stomach. However, the original cause for the release of excess acid remains untreated.

Cimetidine and rantidine are better antacids as they check the actual cause of acidity. These drugs prevent the interaction of histamine with the receptors present in the stomach walls. Thus, there is a decrease in the amount of acid released by the stomach. This is why cimetidine and rantidine are better antacids than sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide.