Background: Stargell was born in Earlsboro, Oklahoma, but later moved to Florida with an aunt after his parents divorced. Later, he returned to Alameda, California, to live with his mother. He attended Encinal High School, where his baseball teammates included future MLB players Tommy Harper and Curt Motton. Stargell signed with the Pittsburgh Pirates organization and entered minor league baseball in 1959.
Context: After retirement, Stargell spent several years as a First Base Coach for the Atlanta Braves from 1986-1988 Wearing #8. He was the first minor-league hitting coach for Chipper Jones. He was inducted into the Baseball Hall of Fame in 1988, his first year of eligibility. He had an awkward interaction with the Pirates that season when the team wanted to schedule a Willie Stargell Night to honor his Hall of Fame election. Stargell refused to participate in the team's plans, still stinging from the team's refusal to even consider him for its managerial job that season. In the 1985 trial of alleged cocaine dealer Curtis Strong, Stargell was accused by Dale Berra and John Milner (both former Pirates teammates) of distributing "greenies" (amphetamines) to players. Berra said that he obtained amphetamines from Stargell and Bill Madlock; he said he could get them from Stargell "on any given day I asked him for one." Stargell strongly denied these charges. Commissioner Peter Ueberroth later cleared Stargell and Madlock of any wrongdoing. Stargell returned to the Pittsburgh club in 1997 as an aide to Cam Bonifay, the team's general manager. He also worked as a special baseball adviser to Pirates owner Kevin McClatchy, who called Stargell "the ultimate class act". Stargell was hospitalized for three weeks in 1999 to treat undisclosed medical problems with one of his organs. A source close to the Pirates blamed Stargell's health issues on his weight gain after retiring as a player. Stargell lost some of that weight, but gained weight again while working for the Pittsburgh front office. After years of suffering from a kidney disorder, he died of complications related to a stroke in Wilmington, North Carolina, on April 9, 2001. In his later life, Stargell had also suffered from hypertension and heart failure. A segment of Stargell's bowel was removed more than two years before he died. He had been in the hospital recovering from a gallbladder surgery at the time of his death. On April 7, 2001, two days before Stargell died, a larger-than-life statue of him was unveiled at the Pirates' new stadium, PNC Park, as part of the opening-day ceremonies.
Question: What was the cause of Willie's death?. Whats the answer?
He had been in the hospital recovering from a gallbladder surgery at the time of his death.