Why does Mentos React With Diet Coke?

Mentos reacts with Diet Coke because of the caffeine, aspartame, potassium benzoate, and carbon dioxide reacting with gum and gelatin in Mentos. Standard Mentos have several tiny holes in the surface which exponentially increases that area for this reaction to occur. Because so many little reactions are happening all at once there is a jet effect as CO2 is formed. You can find more information here: