Schott was hospitalized about three weeks ago for breathing difficulties and frequently was hospitalized in recent years for lung problems. Christ Hospital would not release a cause of death.
Schott had reportedly been on a ventilator during her treatment in the hospital's intensive care unit.
Schott kept a low profile after she ended years of turmoil by selling her controlling interest in the club in October 1999. She appeared at news conferences when she made donations to the zoo and other local organizations.
She remained a limited partner in the team's ownership group, and sued owner Carl Lindner because she didn't like her seats in the new Great American Ball Park, where the Reds moved in 2003.
The Reds had no immediate comment on her death.
Her outspokenness as owner became her legacy and her downfall.
Schott had inherited and expanded her husband's business empire after he died in 1968. Until she took over the Reds in the mid-1980s, she was known as a car dealer who made campy television commercials featuring her beloved St. Bernards.
Once she got control of the front office, she became one of the most prominent figures in the history of baseball's first professional team.
The Reds won the 1990 World Series, sweeping the Oakland A's while Schott rubbed dog hair on manager Lou Piniella and his players.
Two years later, her use of racial slurs created a national controversy that overshadowed the club for nearly a decade. Baseball officials ordered her to watch her comments, but she continued to publicly praise Hitler — saying he was "good at the beginning" but then "went too far" — and make disparaging remarks about ethnic groups.
In May 1996, after hours of consultations with baseball officials, Schott released a statement saying she was sorry her remarks offended people.
"This was not my intent at all," she said. "Let me take this opportunity to set the record straight. I do not and have never condoned Adolf Hitler's policies of hatred, militarism and genocide. Hitler was unquestionably one of history's most despicable tyrants."
With the team's limited owners ready to vote her out as the controlling partner, she sold all but one of her shares to Lindner in 1999 for $67 million.
As she left the spotlight, Schott blamed the other owners for her fate.
"I don't know what I would have done differently, except for stood up and fought with the boys a little more," she said, shortly after the sale was complete.
Growing up in Cincinnati, Schott attended a Catholic girls' school and the University of Cincinnati.
She married Charles J. Schott in 1952 at age 21. When her husband died in 1968 at age 41, she was left with a car dealership, real estate and companies that made bricks and concrete.
Schott bought another car dealership, a garbage dump, cattle and race horses as a prelude to buying the Reds in 1984.
From the moment she bought control, Schott made it clear her tenure would be unconventional. She walked into Riverfront Stadium to announce the sale with her dog Schottzie on a leash. Schott knew little about baseball, but had become its most prominent woman.
She made her first controversial remark at her first news conference, suggesting that women shouldn't be allowed to run a business because they're too emotional. Schott also promised she would stay out of the baseball operations because she didn't know much about it.
Before long, she was involved in every aspect of the team. She moved her office to the stadium, required her personal approval for any purchase of $50 or more, and allowed her dogs to have the run of the place.
She also started making baseball decisions, even though she didn't know the players' names. She settled one contract dispute by flipping a coin.
"I was very much hands-on. I did try and bring some good players in and everything," she said.
She allowed player-manager Pete Rose to grab the headlines through 1989, when he accepted a lifetime ban for gambling. Once he left, she became front-and-center.
Piniella arrived as manager and Bob Quinn became the general manager before the 1990 season, which marked a new phase in Schott's ownership. She became the team's most visible figure as it led wire-to-wire and won the World Series.
While the team won, the organization crumbled. She scrimped on the farm system and scouting, eliminated fan promotions and did away with the marketing that made the Reds a regional draw.
In 1992, the turbulence began. She fired Quinn and drove Piniella away, then went through five managers in six years.
With the shrunken farm system no longer producing, the Reds had to bring in free agents to remain competitive. They had the second-biggest payroll in the National League when they made the playoffs in 1995, then slashing payroll and struggled on the field.
They also started struggling at the gate as Schott's offensive language made headlines. Attendance began falling after 1993, when she was suspended the first time for her remarks.
Schott's troubles multiplied in 1996, when she demanded a new ballpark but refused to campaign for the tax increase that provided funding. She expressed disappointment that opening day was postponed because umpire John McSherry died, eliminated out-of-town score updates to save money, and made more disparaging remarks.
The other owners gave her an ultimatum: Step down or accept another suspension. John Allen took over as managing executive in 1996 and has continued to run the team under Lindner.
She spent the last few years living on her suburban Indian Hill estate and donating money to various causes. She never remarried after her husband died.