When Mario works as a doctor, his persona is called Dr. Mario. Dr. Mario debuted in Dr. Mario on the Nintendo Entertainment System, a puzzle game where the player lines up the colors of Megavitamins to destroy germs.
Dr. Mario also plays in Dr. Mario Express.
Dr. Mario is also an unlockable playable character in Super Smash Bros. Melee. He is unlocked by playing through Classic Mode as Mario. His moves are similar to Mario's, but he is slightly slower and stronger. Dr. Mario also plays in Dr. Mario Express. Dr. Mario also returns as a playable character in Super Smash Bros. for Nintendo 3DS and Wii U and Super Smash Bros. Ultimate.
- In Paper Mario, Tuna says to Mario, "They should call you Dr. Mario."