Gloucestershire's Hamish Marshall hit his fourth century of the season as the visitors made 358 on day one at at Northamptonshire.
The former New Zealand international hammered a brilliant 145 off 197 balls including 19 fours and two sixes to help Gloucestershire recover from a shaky start.
David Willey, Andrew Hall and Muhammad Azharullah each took three wickets for Northants, who then closed on 13 for no loss.
Gloucestershire won the toss and chose to bat but they lost Chris Dent for a four-ball duck in the third over when he edged Willey to Northants wicketkeeper David Murphy.
In Willey's next over, Gloucestershire's wicketkeeper Gareth Roderick was trapped lbw for just two to leave the visitors on nine for two
But Alex Gidman helped his side recover from their poor start by racing to 50 off just 54 ball as part of a partnership of 92 with captain Michael Klinger.
However, Gidman was to throw his wicket away on 59 when he slashed Hall to Willey at point as Gloucestershire reached lunch on 117-3.
Klinger, though, was to fall three runs short of a composed half-century when he was taken by Murphy off the bowling of Hall in the third over of the afternoon.
Marshall went on to complete his 24th century in first-class cricket - and his third in five innings - off 125 balls before Benny Howell completed his half-century off 84 deliveries in the last over before tea.
But Howell fell on 60 early in the evening when he swept Hall to David Sales at deep square leg to break a fifth-wicket stand of 183.
Marshall finally departed two overs after Northants took the second new ball by nudging Azharullah's leg side strangler to Murphy.
James Fuller (nine) followed him back to the pavilion as he was bowled by Willey before Will Gidman chopped Azharullah on to his stumps to walk for 15.
Craig Miles (five-ball duck) and Tom Smith (five) were then pinned lbw by Azharullah and Steven Crook respectively, meaning Gloucestershire's final five wickets had fallen for just 20 runs.