When cocaine and alcohol meet inside a person, they create a third unique drug called cocaethylene. Cocaethylene works like cocaine, but with more euphoria.
So in 1863, when Parisian chemist Angelo Mariani combined coca and wine and started selling it, a butterfly did flap its wings. His Vin Marian became extremely popular. Jules Verne, Alexander Dumas, and Arthur Conan Doyle were among literary figures said to have used it, and the chief rabbi of France said, "Praise be to Mariani's wine!"
Pope Leo XIII reportedly carried a flask of it regularly and gave Mariani a medal.
For the rest of the story: http://www.theatlantic.com/health/archive/2013/01/why-we-took-cocaine-out-of-soda/272694/