Whatever made him ill, it didn't stop Mangini, fired after three seasons with the New York Jets, from taking on one of the NFL's most nauseating situations.
Ten years into their comeback, the Browns remain sickly.
And in this proud football region, where generations of fans know football championships only through stories from their fathers and grainy, black-and-white TV footage, sympathy for the home team is running short.
Along with games, the Browns have lost some dignity since 1999.
"It's been a long 10 years," said kicker Phil Dawson, the lone survivor from Cleveland's expansion season.
In a decade of despair, the Browns are just 54-106 with one playoff appearance and three coaching changes. They've lost at least 10 games in five of the past six years. They've dropped 11 straight to the Pittsburgh Steelers, who no longer consider them their biggest rival.
Projected as Super Bowl contenders following a 10-win season, the Browns tanked in 2008 as dropped passes by wide receiver Braylon Edwards symbolized a plunge from promise. Cleveland lost its last six games without scoring an offensive touchdown, finished 4-12 and forced the ultra-private Lerner, a target for fan abuse, to clean house - again - by firing general manager Phil Savage and coach Romeo Crennel.
Mangini was brought in to fix the mess. No wonder he was queasy.
The man dubbed "Mangenius" by the New York tabloids after taking the Jets to the playoffs in his first season, returned to the Browns - he was a media relations assistant in the early 1990s - with a reputation for being a strict disciplinarian with his players, CIA-caliber secretive with the media, and a stickler for detail.
The scouting report was accurate.
"He's got rules and he expects people to follow them," said linebacker Eric Barton, one of seven former Jets signed by Mangini, who went 23-25 in New York. "If you don't, then there are penalties."
One of Mangini's first moves in Cleveland was to trade enigmatic tight end Kellen Winslow, whose immense talent was too often overshadowed by injuries and controversy. Winslow's departure signaled a cultural shift with the Browns, many of whom abused the good-natured Crennel's kindness.
Mangini placed restrictions on his players' use of cell phones and stereos in the locker room, which has been reconfigured to promote team chemistry. The Browns have been subjected to pop quizzes to make sure they know their playbooks. They are required to learn motivational phrases and Mangini had words like "Focus" and "Finish" spray painted onto the team's practice fields.
During training camp, a mental or physical mistake earned the offending player a lap around the field. Sometimes more than one. Step out of bounds with Mangini, and pay the price. Defensive linemen Shaun Smith and Louis Leonard both recently clashed with their position coach, Bryan Cox, and are no longer wearing orange helmets.
"This has been good for us. We needed discipline," said linebacker D'Qwell Jackson, whose 154 tackles led the league last season. "We had too many guys doing their own thing. We weren't working together as a team like we needed to. There is accountability and guys are buying into coach Mangini's system."
The test for Mangini will come as the losses pile up, and there's little reason to believe the Browns, who will play four games against Pittsburgh and Baltimore in the never-been-better AFC North, will transform into a playoff team overnight. Mangini has added 23 new players to a roster that figures to undergo more changes.
His handling - some say mishandling - of Cleveland's quarterback situation has already brought outside criticism and internal doubt. Mangini spent the summer evaluating every pass, audible and decision made by Brady Quinn and Derek Anderson, whose QB competition dominated camp and the exhibition season.
But with just days left before the Sept. 13 opener against Minnesota, Mangini was keeping his starter a secret. Quinn, who started just three games in his first two pro seasons, is expected to get the nod, but it's not known how much Mangini and his staff believe in the former Notre Dame star.
At some point, the Browns need to pick a quarterback and ride with him. That's what Pittsburgh did with Ben Roethlisberger. It's what Cincinnati did with Carson Palmer. And it's what Baltimore is doing with Joe Flacco. Until Cleveland's quarterback situation is settled, it may be tough for the Browns to escape their current state of malaise.
Cleveland has endured an economic recession for years. It's now coping with football depression.
For the first time in memory, tickets for Browns games are readily available. Last month, the Browns nearly had their first blackout since 1995 for a preseason game and only avoided one by reaching an agreement with their broadcast partner to buy up the remaining tickets. A slow start this season could lead to more disinterest, which was apparent at a training camp lacking its usual buzz.
"I've folded," said 35-year-old fan Michael Hostutler, wearing a No. 19 Bernie Kosar jersey at camp. "This thing is over. There's nothing. I love my Browns, but I'm not hanging my heart on them anymore."
Dawson has lived through Cleveland's downfall. He hopes to experience its rise.
"The fans deserve a winner," he said. "They've been a loyal group of people for a decade. It's time we gave them something to feel good about."