When the Final Smash is activated, Dr. Mario shoots out two large Megavitamins that circle around each other, harming any opponents they hit, potentially knocking them backwards. This move is a clone of Mario's Final Smash, Mario Finale, but is stronger. It also makes the Megavitamin contact sound.
In Dr. Mario's Final Smash, he spreads his arms wide and then lets loose a pair of giant vitamin capsules that spiral through the air, taking out any pesky "viruses" in their path. Their wide range makes them tough for foes to avoid, and opponents they strike will take multiple hits, possibly even being pushed right off the screen!
In Dr. Mario, Megavitamins were used to eliminate viruses. When the player lines up four vitamins and/or viruses of the same color, the vitamins and the viruses are destroyed. In most Dr. Mario games, they appear in three colors; red, blue and yellow.