Colin Kaepernick passed for a touchdown and ran for another as visiting San Francisco returned a pair of interceptions for scores to outgun New Orleans.

Making the start for the healthy but demoted Alex Smith, Kaepernick completed 16 of 25 passes for 231 yards and added six rushes for 27 yards. Frank Gore racked up 101 all-purpose yards and a touchdown while San Francisco (8-2-1) posted its first interception-return TDs of the season.

Drew Brees went 26-for-41 for 267 yards with three touchdowns as the Saints (5-6) lost for just the second time in their last seven games. Ten different New Orleans players caught passes, led by Darren Sproles' seven receptions for 65 yards.

After Kaepernick opened the scoring with a 7-yard run, Brees evened things with a 6-yard TD pass to tight end David Thomas late in the first quarter. A 10-yard strike to Marques Colston gave New Orleans the lead near the midway point of the second quarter, but Ahmad Brooks stepped in front of a Brees pass and returned it 50 yards for a score to send the teams to the break tied at 14.

Gore's first touchdown catch since Week 5 of the 2010 season put the 49ers back in front 2:43 into the third quarter. Donte Whitner doubled the advantage with a 42-yard interception return for a score on a pass intended for Colston. Brees' third TD pass of the day, a 2-yard strike to Jed Collins midway through the period, made it a one-touchdown game but the Saints wouldn't get any closer.

GAME NOTEBOOK: Smith (concussion) was activated and served as the backup. San Francisco head coach Jim Harbaugh wouldn't tip his hand on his Week 12 starter until Saturday, saying the uncertainty gave his team a small advantage. ... Colston was injured on Whitner's interception return. He left the field on his own power and returned after passing his concussion tests. ... Brees extended his NFL-record streak of consecutive games with a touchdown to 54.