"I Need a Doctor" is a single by American hip-hop artist Dr. Dre. The song features guest appearances from American rapper Eminem and singer Skylar Grey. The song is produced by British record producer Alex da Kid, mixed by Dr. Dre, and was released for digital download through the American iTunes Store on February 1, 2011.

Musically, "I Need a Doctor" is predominantly a rap song, backed by a "spacey," drum-heavy production, with extra piano keys featured in the introduction and the chorus. However, it also incorporates elements of other genres, particularly pop music with the Skylar Grey-sung chorus and the unusually serious subject matter, much different to the topics covered on Dr. Dre's previous music, especially on his previous two studio albums The Chronic (1992) and 2001 (1999). Lyrically, the song is largely about Dr. Dre and Eminem's close friendship, and how they have often needed and inspired each other in the past.

Due to the song being leaked onto the Internet several months in advance to its release, it was a significant commercial success on its official release, particularly in the United States, where it peaked at number 4 on the Billboard Hot 100, becoming Dr. Dre's second highest peaking song on the chart ever, and also peaking in the upper regions of many national charts. As of October 2011, it has sold over 2,206,000 digital copies in the United States alone, making it Dr. Dre's first song to reach the landmark.

"I Need to Know" is a song by Marc Anthony, and was released as the lead single of his first English language album Marc Anthony, in August 1999.

The song was written and produced by Marc Anthony and Cory Rooney, and also a Spanish version (titled Dímelo) was released with the collaboration of Robert Blades and Angie Chirino, and the lyrics are about a man who wants to know about a woman's feelings for him, going with the title "I need to know". Both versions of the track were very successful in the United States. The English version peaked at number 3 in the Billboard Hot 100 and at number-one in the Hot Latin Tracks for 5 consecutive weeks.

This track received three Latin Grammy nominations, Song of the Year, Record of the Year and Best Male Pop Vocal Performance, winning for Song of the Year at the Latin Grammy Awards of 2000. Also on the Grammy Awards received a nomination for Best Male Pop Vocal Performance, which lost out to Sting's "Brand New Day".

"I Need To Know" was included on the compilation album NOW: That's What I Call Music Vol. 4. "Dímelo" was included on the compilation album released for the 1st. Latin Grammy Awards, since it was nominated for "Record of the Year".

Holly Brook Hafermann (born February 23, 1986) better known by her stage name Skylar Grey, is an five-time Grammy-nominated American multi-instrumentalist, singer, songwriter, and record producer. Grey was signed to Machine Shop Recordings under the name Holly Brook. She released her debut album as Holly Brook, Like Blood Like Honey, in 2006. She co-wrote the three versions of "Love the Way You Lie" (for Eminem and Rihanna) with Alex da Kid, who signed her to his Wonderland Music label. She was featured as a guest vocalist on Fort Minor's "Where'd You Go" and "Be Somebody", Diddy-Dirty Money's "Coming Home", Dr. Dre's "I Need a Doctor", Lupe Fiasco's "Words I Never Said" and Kaskade's "Room for Happiness".

Grey performed professionally as a child in a folk duo with her mother called Generations. Together, (with producer/engineer Randy Green) they independently produced three albums, Dream Maker, Lift Me, and Millennial Child/Waiting For You. Grey started her first band at the age of fifteen after 'sneaking' into bars, working with jazz musicians including Jeff Eckles, Tim Whalen and Leo Sidran in Madison, Wisconsin.

Andre Romelle Young (born February 18, 1965), better known by his stage name Dr. Dre, is an American rapper, record producer, record executive, entrepreneur, and occasional actor. He is the founder and current CEO of Aftermath Entertainment and a former co-owner and artist of Death Row Records. He has produced albums for and overseen the careers of many rappers, including Snoop Dogg, Eminem, 50 Cent and Game. As a producer he is credited as a key figure in the popularization of West Coast G-funk, a style of rap music characterized as synthesizer-based with slow, heavy beats. As of 2011, Dr. Dre is ranked as the third richest figure in the American hip hop scene by Forbes with a net worth of $250 million.

Dre began his career in music as a member of the World Class Wreckin' Cru and he later found fame with the influential gangsta rap group N.W.A with Eazy-E, Ice Cube, MC Ren, and DJ Yella which popularized the use of explicit lyrics in rap to detail the violence of street life. His 1992 solo debut, The Chronic, released under Death Row Records, led him to become one of the best-selling American performing artists of 1993 and to win a Grammy Award for the single "Let Me Ride". In 1996, he left Death Row to establish his own label, Aftermath Entertainment. Under that label, he produced a compilation album titled Dr. Dre Presents the Aftermath in 1996, and released a solo album titled 2001 in 1999, for which he won the Grammy producer's award the next year.