Step 1 : Introduction to the question "7-Up originally contained which substance as an ingredient?"
The original recipe for 7-Up contained lithium as an ingredient. In fact, 7-Up was originally called "Bib-Label Lithiated Lemon-Lime Soda" when it was created in 1929. The drink contained lithium citrate, a mood-stabilizing drug, in its formula until 1948, when the U.S. Food and Drug Administration outlawed usage of the chemical in soda drinks. They eventually abandoned the original name of the popular soft drink and called it 7-Up. It has been theorized that the “7" actually refers to the atomic mass of lithium.