7-Up was originally formulated with... lithium!

"The drink was originally marketed as a hangover cure - due to the inclusion of lithium citrate. It was released just a few years before the Wall Street crash of the 1920s and it was marketed under the name “Bib-Label Lithiated Lemon-Lime Soda” - quite a mouthful! The name was changed to 7-Up shortly after its release but lithium remained one of the ingredients until 1950.

Some popular myths surround the name of the drink - but the name is most likely due to the original recipe containing 7 ingredients (with the “up” portion relating to the lithium) or the fact that lithium has an atomic mass of 7."