Gordon D'Arcy and Jack Adams both scored tries at Lansdowne Road
Leinster (30) 37
Tries: D'Arcy, Contepomi, Keogh, Horgan.
Cons: Contepomi (4)
Pens: Contepomi (3)
Gloucester (17) 20
Tries: Foster, Adams
Pens: Lamb (2)
Cons: Lamb (2)
Leinster produced a typically attacking display to hold off battling Gloucester in Saturday's Heineken Cup clash.
Gordon D'Arcy's early Leinster try was cancelled out by Mark Foster's super score as Gloucester took a 10-7 lead.
However, Leinster then hit 23 points without reply, including tries from Felipe Contepomi and Stephen Keogh.
Jack Adams' touchdown helped Gloucester reduce Leinster's lead to 10 points but Shane Horgan's try made the game safe and secured the bonus point.
Leinster started in typically flowing fashion at Lansdowne Road with D'Arcy touching down after Brian O'Driscoll's decoy run had out-foxed Adams.
Contepomi added the Leinster extras but the young Gloucester side replied quickly to edge into a 10-7 lead with Mark Foster beating O'Driscoll's tackle before touching down.
Lamb's conversion added to his earlier penalty which put Gloucester 10-7 ahead.
However, Leinster forged again by the 13th minute with Contepomi scoring a scrappy try under the posts after Girvan Dempsey had squandered a chance moments earlier.
Contepomi converted to extend Leinster's lead to 14-10 and the Argentine fly-half added to the Irish province's lead with three successive penalties.
Leinster stretched their advantage to 30-10 when Stephen Keogh finished off a breakaway move started in their own 22 after Iain Balshaw had spilled a Ryan Lamb pass.
But Gloucester still had time to hit back in first-half injury-time when Jack Adams split the Leinster defence to score under the posts with Lamb adding the extras.
Gloucester put Leinster under pressure after half-time and another Lamb penalty cut the home side's lead to 10 points.
But despite having Malcolm O'Kelly sin-binned, Leinster then notched the decisive try in the 62nd minute with Horgan touching down to ensure his side's bonus-point.
Leinster flanker and man-of-the-match Keith Gleeson:
"We're not going to get too carried away at this stage. We got off to a good start by getting the bonus point.
"You can't win the cup at this stage but you can certainly lose it.
"It's important that we win our home games but next weekend against Edinburgh will be very tough.
"We'll have to produce a much better performance that we did tonight."
Gloucester director of rugby Dean Ryan:
"Over the first 30 minutes we didn't show a lot of maturity in how we played in our own half and that gave an outstanding backline too many opportunities.
"The Heineken Cup doesn't allow you to make loose decisions without being punished but we will learn from this type of experience."
Leinster: Dempsey, Horgan, O'Driscoll, D'Arcy, D Hickie, Contepomi, Willis, McCormack, Blaney, Green, Hogan, O'Kelly, Keogh, Gleeson, Heaslip.
Replacements: Dunne for Willis (80), Vermaas for Blamey (74), Corrigan for Green (71), Byrnes for Hogan (74), Finnigan for Keogh (75).
Not Used: Lewis, Fitzgerald.
Sin Bin: O'Kelly (55).
Gloucester: Balshaw; Bailey, Adams, Allen, Foster; Lamb, Richards; Califano, M Davies, Nieto; Bortolami (capt), Eustace; Buxton, Hazell, Forrester.
Replacements: Mercier for Forster (58), Lawson for Richards (54), Wood for Califano (64), Azam for M. Davies (71), Pendlebury for Eustace (72), Boer for Hazell (44).
Not Used: Keil.
Referee: Christophe Berdos (France).