Benni McCarthy scored two penalties as Blackburn swept luckless Bolton aside.
McCarthy scored his first goals for five games to set up the win
McCarthy blasted home after Gretar Steinsson fouled David Dunn but replays suggested the ball was won cleanly.
Bolton were again unfortunate when Kevin Nolan struck the bar but Kevin Davies fired them level following a punt forward from Ivan Campo.
McCarthy netted after Cahill fouled Dunn, David Bentley headed in the third from Dunn's cross and Morten Gamst Pedersen swept in a fourth at the end.
Blackburn's first victory in five games - which completed the double over their local rivals - boosts their hopes of qualifying for the Uefa Cup, while Bolton will reflect on a week of mixed fortunes.
Boss Gary Megson rested half the team which achieved a superb draw at Atletico Madrid to progress in the Uefa Cup on Thursday.
Those that were retained had not even broken sweat when Jussi Jaaskelainen parried McCarthy's effort inside the first 10 seconds.
Bolton almost had an early goal of their own when El Hadji Diouf's shot was kept out by Friedel after Davies flicked the ball on following a throw-in.
After that bright opening, the first half became niggly, punctuated by badly timed challenges and accusatory insults.
There was more uproar when Dunn went down under a challenge from Steinsson on the left edge of the area and, after the protests had subsided, McCarthy cracked the ball in just to the right of centre.
Bolton's feelings of injustice were not helped when skipper Nolan's side-footed effort crashed against the woodwork after Diouf's shot had been pushed out by Friedel.
But they took the game by the scruff of the neck after Megson brought on Grzegorz Rasiak at half-time.
Davies bundled home after Zurab Khizanishvili jabbed the ball straight to him following Campo's hopeful ball forward and Friedel thwarted Cahill with his legs when the defender was left all alone to control a deep free-kick from Campo.
However, totally against the run of play, Rovers were back in front when Cahill took out Dunn from behind, and McCarthy again belted in a straightish spot-kick.
Four minutes later the game was over as a contest when Bentley headed in at the far post from Dunn's cross from the left.
Nolan was lucky to stay on the pitch in the aftermath as the red mist descended over the aggrieved Wanderers.
He was immediately taken off by Megson, whose team will need to show more composure if they are to pull clear of relegation danger.
Friedel pulled off another good save from Ricardo Gardner in the closing stages before Pedersen rifled in with the last kick of the game at the far post following a cross from substitute Jason Roberts.
Blackburn boss Mark Hughes:
"People are telling me there was a bit of doubt over the first penalty, well over the course of the season these things go for and against you.
"Overall Bolton can't have any real complaints about the result - we were good value for the win. We played some good stuff, particularly in the first half.
"It's a little bit harsh on Bolton because they did cause us problems but in the end we deserved the win.
Bolton manager Gary Megson:
"For the first penalty it's a corner. He's a good referee but he's made a huge mistake because it's changed the game.
"In the first half we weren't anything like I know we can be. We continually let them have too much time on the ball.
"But in the second we were looking like we were going on to win it. If we had changed the way we went about the first half with what we did in the second we would have got a better result."
Blackburn: Friedel, Emerton, Samba, Khizanishvili, Warnock, Bentley, Reid, Dunn (Mokoena 77), Pedersen, Santa Cruz, McCarthy (Roberts 82).
Subs Not Used: Brown, Kerimoglu, Derbyshire.
Booked: Reid, Dunn.
Goals: McCarthy 25 pen, 67 pen, Bentley 71, Pedersen 90.
Bolton: Jaaskelainen, Steinsson, Cahill, Andrew O'Brien, Gardner, Nolan (Cohen 76), Campo (Joey O'Brien 76), Taylor, Guthrie (Rasiak 46), Davies, Diouf.
Subs Not Used: Al Habsi, Meite.
Booked: Nolan, Guthrie, Campo, Diouf.
Goals: Davies 50.
Ref: Mark Clattenburg (Tyne & Wear).
BBC Sport Player Rater man of the match: Blackburn's David Bentley on 7.73 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.