Gloucester ended London Irish’s run of five successive wins to regain pole position in the Guinness Premiership.
West country rivals Bath had briefly taken the lead with their home victory over Newcastle – but the Cherry and Whites were soon back on top.
Head coach Dean Ryan gave a debut to Irish lock Dan Tuohy and included young backs Charlie Sharples and Dan Norton on the bench.
The Exiles had Argentina international Juan Leguizamon back at blindside flanker and former All Black Clarke Dermody on the replacements bench.
With Paul Hodgson on England duty, Warren Fury started at scrum-half – with midweek signing Ross Blake, the Cambridge University number nine, among the replacements.
In driving rain, the visitors missed early chances – full-back Peter Hewat off target with a penalty from 30 metres.
Gloucester were quickly up the other end, and a neat grubber kick fell for prop Nick Wood to plough through and touch down by the posts.
A second try followed as full-back James Bailey broke down the right, before kicking ahead. Centre Jack Adams capitalised as the Exiles made a mess of collecting the loose ball, winning the race for the touchdown.
Fly-half Willie Walker added the simple conversions to both tries before Hewat found his target with a 20-metre penalty midway through the half.
The London Irish defence was again exposed as left wing Mark Foster collected a kick ahead from Tuohy before racing through to touch down by the posts – and Walker added the extras.
With five minutes of the half remaining, Gloucester hooker Andy Titterrell was at the centre of a tussle on the ground.
When referee David Rose restored order, by speaking to the players involved and the two captains, he awarded Gloucester a penalty – which Walker slotted between the uprights.
Titterrell had to leave the field for treatment, and his replacement Olivier Azam was soon sent to the sin-bin for foul play.
Hewat kicked the resultant penalty, but Gloucester nonetheless led 24-6 at the break.
The visitors started the second half the stronger up against 14 men and continued to dominate when Gloucester were back to full strength – Hewat landing his third penalty from in front of the posts.
London Irish reduced the arrears further as wing Topsy Ojo intercepted a pass 15 metres inside his own half before outpacing two Gloucester players to touch down – but Hewat was off target with his conversion attempt.
Walker had a similar problem with his next penalty kick but then found the mark midway through the half.
Nothing seemed to be going for the Exiles – and with five minutes remaining, David Paice was sent to the sin-bin.
Gloucester made the most of the extra man and drove the visitors back over their own line.
But referee Rose consulted with the television match official Graham Hughes before awarding the bonus-point try through Titterrell. Walker added the conversion.