Rolaids are a chalky antacid product (made by Pfizer) that were originally invented in the 1920s but did not really gain prominence in the American subconscious until the "How do you spell relief?" advertising campaign back in the early 1970s.
Rolaids are basically just Calcium carbonate and Magnesium hydroxide combined with various flavoring agents. Today they come in plastic bottles, however they were originally rolled up in foil like "Lifesavers" candy. This original packaging is the source of their name.
Ironically enough the possible side effects of this antacid include vomiting, loss of appetite, constipation and stomach cramps.