Dr. Mario 64 is a puzzle video game developed by Nintendo for the Nintendo 64, released in 2001. In the game, players control Dr. Mario as he battles a flu outbreak using colored capsules known as Megavitamins. Wario, seeking recognition, attempts to steal the Megavitamins but fails. The adventure unfolds as Dr. Mario and Wario pursue the villains Mad Scienstein and Rudy the Clown to reclaim the Megavitamins.
The flu season has come about, and it's Dr. Mario's duty to use his Megavitamins to heal the people of the land. However, Wario, wanting to have the fame that Dr. Mario has, attempts to steal the Megavitamins, but to no avail. Afterwards, Mad Scienstein and Rudy the Clown (from Wario Land 3) steal the Megavitamins, and both Dr. Mario and Wario give chase.