Sam Allardyce has been complaining that bad refereeing has cost Bolton points this season, but a brilliant decision by Alan Wiley gave Wanderers the perfect start.
The referee waved play on after a crunching tackle by Jacob Burns left Kevin Nolan writhing on the floor.
The ball was switched quickly to Youri Djorkaeff and the French international gave Pedersen an unmissable chance from close range.
However, Bolton failed to cash in on their advantage. After a minute spent treating Nolan, the game restarted and Leeds immediately equalised.
Stephen McPhail threaded a ball into the path of Harry Kewell who picked out Alan Smith, and the four-goal hero of Florence made no mistake with his shot.
With Lee Bowyer suspended, Olivier Dacourt, Eirik Bakke, Lucas Radebe, Ian Harte and Dominic Matteo injured, and Mills on compassionate leave, Leeds had a makeshift look.
Burns made his first start for two years, alongside McPhail, with Jason Wilcox filling in at left back and throughout the opening period Venables' team struggled for shape and rhythm.
Bolton, in contrast, were working hard and playing fluently with Bernard Mendy dangerous down the right flank, Per Frandsen dominating the centre of the park, and Anthony Barness doing an outstanding job marking Smith.
Leeds started the second period brightly with Bruno N'Gotty twice making important interventions to deny Mark Viduka shooting chanes, while Smith almost produced a wonder goal, turning on a sixpence but his fierce shot went inches over.
But the longer the half went on the more dangerous Bolton became. Pedersen outran Jonathan Woodgate and fired across Paul Robinson only for the ball to come back into the keeper's arms off the post.
But there was no mistake when Djorkaeff created a big hole in the defence and slotted the ball wide of the Leeds keeper.
But once again Bolton could not hold on to their lead. Smith found Kewell unmarked to his left and the Aussie made no mistake from six yards.
Djorkaeff had a great chance to seal things in the closing minutes but Robinson denied him.
However, within a minute the keeper pulled down Ricketts to give away a penalty that the former Walsall striker converted himself before Pedersen volleyed home a fourth with the last kick of the game.