The loss was only the fifth in the last 17 games for the Cubs, as the Marlins snapped their home win streak at six games.
"We started out looking good, cruising kind of, and the thing just kind of hit the fan and it happened quick," Wood said.
Wood did not give up a hit until Lee singled to lead off the fourth and moved up on Justin Ruggiano's fly ball to right. One out later, Austin Kearns hit an RBI single and Infante followed with his eighth home run to put Miami ahead, 3-0.
The Marlins loaded the bases in the fifth on singles by Anibal Sanchez, Jose Reyes and Emilio Bonifacio. Bonifacio had bunted, and Wood tried for the force at third, but was too late with a shovel pass. Lee followed with his 17th career grand slam to open a 7-0 lead.
"He's one of the best hitters in the game," Cubs catcher Geovany Soto said of Lee. "You've got to respect that."
It was Lee's first home run with the Marlins, and 39th against the Cubs, his most against any team.
"[Wood] was pretty sharp early, making pitches on both sides of the plate," Cubs manager Dale Sveum said. "Carlos got a base hit [in the fourth] on a changeup, and bounced one by [Starlin] Castro there, and then the home run made it 3-0, and it seemed like the next inning, [Wood] didn't come out with much command, couldn't keep the ball down and everything was up.
"He didn't use a whole lot of his offspeed stuff to pitch inside to both sides of the plate tonight. He pitched away tonight. I think he only threw maybe 10 offspeed pitches out of 92 or whatever he finished with. He kind of got out of rhythm and got out of whack there."
The Cubs had chances, beginning in the first inning when both David DeJesus and Starlin Castro singled. But Anthony Rizzo grounded into a double play -- he also did so in the eighth -- and Alfonso Soriano struck out to end the inning.
"We put together some hits," Sveum said. "We just couldn't break it open when we got guys on, first inning, first and second. That was kind of a key [point] in the game. First and second, after [Wood] shut them down in the top of the first, things could've changed there."
The difference, Soto said, may have been that the Marlins were patient.
"I felt in the fourth, and going into the fifth, it felt like [Wood's] command was there, but they were laying off some great pitches, and he normally gets swings on them," Soto said. "It happens sometimes. I thought he threw the ball real well. ... He's been throwing the ball phenomenally. That's a good lineup over there."
The Cubs didn't score until the fifth when Jeff Baker hit a solo home run off Sanchez (5-6), and they added another run when Soto doubled and scored on a fielding error by Ramirez, who couldn't get his glove on pinch-hitter Joe Mather's grounder. Luis Valbuena hit a two-run double and scored on Baker's single in the eighth off Chad Gaudin.
"Those guys, you don't pay attention, they'll score a lot of runs," Marlins manager Ozzie Guillen said of the Cubs. "They've got a couple hitters there, [Bryan] LaHair and that Rizzo kid, they swing the bat good. Their lineup is pretty strong. You have to respect the lineup, and that's why I brought everybody out of the bullpen."
Despite the loss, Sveum said he had seen improvement by Wood, who has added a more effective backdoor cutter.
"He had never in his wildest dreams thought he'd throw a backdoor cutter and use that side of the plate, and obviously, it's opened up a whole new world for him to get hitters leaning out there," Sveum said. "Now you can come in with your cutter and four-seamer inside, and it just opens up everything. You get a lot more cheap outs that way when you get hitters leaning out over the plate instead of having their eyesight in one spot all the time."
This was Wood's first start since July 6 because of the All-Star break, but he didn't blame the layoff.
"Every time you get the ball, you know it's your day to pitch," the lefty said. "It's been 11 days with the All-Star break and everything, but I got my work in. It just wasn't my night tonight."