Los Angeles County Asst. Chief Coroner Ed Winter said an overdose of Promethazine/Codeine syrup and sleep apnea contributed to the death of Chad Butler, known in the rap world as Pimp C.
Promethazine/Codeine, a cough syrup, is a drug that is frequently referred to in music lyrics.
Winter said Butler's death has been ruled an accident.
Butler was found dead in a room at Los Angeles' Mondrian Hotel, a longtime music industry hangout not far from the House of Blues on Sunset Strip, where he had performed Dec. 1 alongside rap veteran Too $hort.
Pimp C and partner Bun B were pioneers of Southern rap and hit the mainstream with their cameo on Jay-Z's hit "Big Pimpin'." UGK, along with Geto Boys, are considered to be one of the people responsible for introducing Texas as the "third coast" of hip-hop.
The duo's career was derailed when Butler was jailed for three years in 2002 on gun charges. He released an album while in prison and this year the group made a comeback with the critically acclaimed album "Underground Kingz," which included the hit "Int'l Player's Anthem (I Choose You)," featuring OutKast.