Answer by taking a quote from the following article:

Andy Warhol (; born Andrew Warhola; August 6, 1928 - February 22, 1987) was an American artist, director and producer who was a leading figure in the visual art movement known as pop art. His works explore the relationship between artistic expression, celebrity culture, and advertising that flourished by the 1960s, and span a variety of media, including painting, silkscreening, photography, film, and sculpture. Some of his best known works include the silkscreen paintings Campbell's Soup Cans (1962) and Marilyn Diptych (1962), the experimental film Chelsea Girls (1966), and the multimedia events known as the Exploding Plastic Inevitable (1966-67). Born and raised in Pittsburgh, Warhol initially pursued a successful career as a commercial illustrator.

Warhol died in Manhattan at 6:32 a.m. on February 22, 1987 at age 58. According to news reports, he had been making a good recovery from gallbladder surgery at New York Hospital before dying in his sleep from a sudden post-operative irregular heartbeat. Prior to his diagnosis and operation, Warhol delayed having his recurring gallbladder problems checked, as he was afraid to enter hospitals and see doctors. His family sued the hospital for inadequate care, saying that the arrhythmia was caused by improper care and water intoxication. The malpractice case was quickly settled out of court; Warhol's family received an undisclosed sum of money.  Shortly before Warhol's death, doctors expected Warhol to survive the surgery, though a revaluation of the case about thirty years after his death showed many indications that Warhol's surgery was in fact riskier than originally thought. It was widely reported at the time that Warhol died of a "routine" surgery, though when considering factors such as his age, a family history of gallbladder problems, his previous gunshot wounds, and his medical state in the weeks leading up to the procedure, the potential risk of death following the surgery appeared to have been significant.  Warhol's brothers took his body back to Pittsburgh, where an open-coffin wake was held at the Thomas P. Kunsak Funeral Home. The solid bronze casket had gold-plated rails and white upholstery. Warhol was dressed in a black cashmere suit, a paisley tie, a platinum wig, and sunglasses. He was laid out holding a small prayer book and a red rose. The funeral liturgy was held at the Holy Ghost Byzantine Catholic Church on Pittsburgh's North Side. The eulogy was given by Monsignor Peter Tay. Yoko Ono and John Richardson were speakers. The coffin was covered with white roses and asparagus ferns. After the liturgy, the coffin was driven to St. John the Baptist Byzantine Catholic Cemetery in Bethel Park, a south suburb of Pittsburgh.  At the grave, the priest said a brief prayer and sprinkled holy water on the casket. Before the coffin was lowered, Paige Powell dropped a copy of Interview magazine, an Interview T-shirt, and a bottle of the Estee Lauder perfume "Beautiful" into the grave. Warhol was buried next to his mother and father. A memorial service was held in Manhattan for Warhol on April 1, 1987, at St. Patrick's Cathedral, New York.

were drugs involved?
Warhol died of a "routine" surgery, though when considering factors such as his age, a family history of gallbladder problems, his previous gunshot wounds,