Dr. Mario is a series of puzzle games by Nintendo and it's a sub-series of the Mario series.
The original games are:
Dr. Mario (July 27, 1990), Famicom/Nes, Game Boy. Also released in 1998 for Super Famicom, while the NES version was re-released in 2004 for Game Boy Advance and the Game Boy version was re-released in 2011 for 3DS Virtual Console.
Dr. Mario 64 (April 9, 2001), Nintendo 64. Re-released in 2003 for GameCube within Nintendo Puzzle Collection, retitled Dr. Mario.
Remakes and compilations are:
Vs. Dr. Mario (1990), Arcade. A remake of the original game.
Tetris & Dr. Mario (December 1994), SNES. A compilation including the original game.
Dr. Mario & Germ Buster (March 25, 2006) known as Dr. Mario Online Rx in America. A remake of Dr. Mario also including Germ Buster mode from Brain Training
A Little Bit of... Dr. Mario (Dicember 24, 2008), Nintendo DSiWare. A remake of Dr. Mario.
Dr. Mario & Puzzle League (September 13, 2005), Game Boy Advance.
Dr. Mario: Miracle Cure (May 31, 2015), Nintendo 3DS. A new version of Dr. Mario, including a new mode with special items.
Additionally a comic based on Dr. Mario was released on issue 9 of Nintendo Comics System, as part of the Super Mario Bros. comic series.