Carlos Gomez added a two-run homer in the fourth for Milwaukee.
Lohse (6-1) was sharp while going eight innings to win his sixth straight decision. He gave up one run on four hits with no walks and eight strikeouts. Lohse's only loss of the season came against the Braves on April 1.
After being shut out 5-0 Tuesday night, the Brewers skipped batting practice Wednesday and then jumped on Ervin Santana (4-2) in the first inning. Gomez singled, Scooter Gennett doubled and Jonathan Lucroy took a one-out walk before Reynolds' third career grand slam - a line drive over the left-field wall.
Reynolds snapped a 0-for-12 streak with his ninth homer.
The Braves scored their only run off Lohse in the first inning on back-to-back doubles by Freddie Freeman and Justin Upton, who had three hits. Lohse did not allow another baserunner to reach second base. Atlanta's only other hits off Lohse were singles by Jason Heyward in the third and Upton in the seventh.
Upton had a two-out single off Rodriguez in the ninth before Chris Johnson's third strikeout ended the game.
The Brewers took advantage of Santana's two-out walk to Lohse in the fourth. Gomez followed with a high homer, his 10th, over the center field wall.
Gomez circled the bases without incident, avoiding a repeat of an ugly melee on Sept. 25, 2013. Last season, Gomez was slow to leave the batter's box following a homer at Turner Field, he exchanged words with Braves infielders as he circled the bases and then was blocked at home plate by former Atlanta catcher Brian McCann. That led to a brawl that emptied both dugouts.
Santana allowed a season-high six runs on nine hits and four walks in seven innings.
The Brewers' two homers matched the total allowed by Santana in his first seven starts. Santana has lost three of his last four starts, and the last two have been ugly. The right-hander allowed five runs on 10 hits in five innings in a 5-2 loss at St. Louis on Friday.
Santana, 3-1 with a 1.95 ERA in April, has seen his ERA climb to 3.42.
NOTES: Brewers manager Ron Roenicke said he doesn't think RHP Yovani Gallardo, who left Tuesday night's game after spraining his left ankle, will land on the DL. Roenicke said Gallardo must make dramatic improvement to avoid missing his next scheduled start on Sunday at Miami. "It's got to be a lot better tomorrow," Roenicke said. ... Braves C Evan Gattis missed his second straight game with viral symptoms, but was available off the bench, according to manager Fredi Gonzalez. ... Lohse improved to 4-0 in six career starts at Turner Field. ... The four-game series ends Thursday night with Braves RHP Aaron Harang facing Brewers RHP Matt Garza.