Verified answer

According to Mythbusters it has to be diet Coke and regular Menthos for it to work.Something about the chemical makeup of both products

This happens because there is a reaction between the carbonated beverage and Mentos candies. The numerous small pores on the candy's surface catalyze the release of carbon dioxide (CO2) gas from the soda, resulting in the rapid expulsion of copious amounts of foam. When the candies come into contact with the liquid, a reaction causes the formation of foam at a rapid rate. This rapid formation of foam causes pressures too intense for the container to endure, thus causing the explosion!!!

This only works with Diet Coke.

http://youtu.be/u6kcNi4qDLk

They used diet coke.