Cocaine Cocktail

Coca-Cola was originally developed as a headache remedy.
It had trace amounts of cocaine until 1906,
when it was removed because of tighter health regulations.

In spanish, the term Cola means tail, glue, queue and rear.
Perhaps the inventor was making a pun for "Cocaine Cocktail".

From IC: It's The Rear Thing!

http://en.wikipedia.org/wiki/Coca_cola