Many decades ago, medicated soft drinks were all the rage and people could not get enough, unaware of the risks associated with chemicals they were ingesting. Introduced in 1929 as Bib-Label Lithiated Lemon-Lime Soda, the drink now known as 7-Up once contained lithium citrate, a mood-stabilizing drug. Lithium was taken out of the formula in 1950, but chemists at the University of Nottingham in England recently conducted an experiment to see what would happen to the drink if the chemical were reintroduced.

The scientists set out to test how the lithium changed the acidity of the soda. The results are fascinating to watch, from the bubbling when the lithium first comes into contact with the soda to the moments when the concoction changes from light green to a deep brown to red to black. Sir Martyn Poliakoff, the host of the segment on the Periodic Videos YouTube channel, tackles the scientific explanations in the video above.

The results of the experiment aren't definitive, but there is a clear reason why lithium (which is still used as a medication) was taken out of the drink. There is a very thin line between therapeutic and toxic when it comes to ingesting lithium, so high concentrations (like the amount used in the experiment) could be harmful. Watch the clip above to learn more about what happens at the chemical level when the two are combined.

Banner image via Periodic Videos on YouTube

[h/t Gizmodo]