If there’s one thing director Nick Cassavetes knows, it’s how to direct a hysteric Cameron Diaz.

Last time he worked with her, on “My Sister’s Keeper,” he made her a nut job. His new collaboration, “The Other Woman” (Rated PG-13; 109 Min.), practically makes her an alcoholic to elicit audience giggles. She wakes up from no less than six hangovers by the end of this saga.

That drunken stagger is an accurate representation of the way the movie progresses, jumping from manic potty humor to absurd violence. Diaz plays Carly, a high-powered lawyer who can apparently up and abandon her job whenever she wants. She takes a detour when she discovers her new beau Mark (Nikolaj Coster-Waldua) is actually a philanderer married to Kate (Leslie Mann) and also dating Amber (Kate Upton). There’s also another unnamed mistress. Well, there’s like three other unnamed mistresses. Mark is pretty much the worst guy ever.

The three team up to take Mark down, but this doesn’t come until about an hour into the movie. The much better portion of the movie comes before that, when Kate tries to bond with Carly over their lying/cheating husband/boyfriend.

The best scene comes early on when the two go out for drinks and Carly ends up having to get Kate into a cab. Of all the scenes these women are drunk, Mann’s performance is tops. She’s given the chance to lead a film and she doesn’t let the opportunity escape her. Mann lets her hair down, not restricted by her uptight Debbie character from Judd Apatow’s films (Mann and Apatow are married in real life).

But even Kate gets a little old as the movie overstays its welcome, cycling through two or three series of Kate forgiving her husband before realizing once again that he’s cheating on her with at least THREE other women. The movie purports to be about girl power but the way these girls are inexplicably drawn back to Mark because of his cheesy romantic pickups is slightly offensive.

What’s most disappointing about “Woman” is the way it basks in diarrhea and manboob jokes in lieu of the dark comedy it could’ve been. Mark is clearly a sociopath who’s also involved in illegal business activities. The women cycle through several different revenge schemes, feeding him hormones and putting hair remover in his shampoo. Then Carly gives him a laxative, leading to an extended poop joke. Just because Melissa McCarthy made it funny in “Bridesmaids” does not mean it needs to be rehashed here.

These juvenile scenes are a symptom of a much larger problem: “The Other Woman” is too unsure of whether to make light of its surprisingly dark plot. A better director with a better cast could’ve made something fresh with this material. As strange as it sounds, the film occasionally diverts into Coen Bros. territory. When Mark gets his ultimate comeuppance, the scene is ridiculous and violent. But it’s played for light laughs. You’d think a scorned 15-year-old wrote the screenplay.

The movie also falters in acting beyond its three leads. Nicki Minaj is grating in her first live-action performance as Carly’s secretary. The biggest offense comes from Taylor Kinney as Kate’s brother Phil, set up as the eventual romantic interest for Carly from square one. Kinney has two emotions — frustrated and happy — and displays them so robotically it seems the filmmakers actually CGI’ed him into the film. There hasn’t been a more phoned-in performance this year.

“The Other Woman,” specifically Leslie Mann, may seem like an oasis of romantic comedy in the desert of downtrodden films we’ve had this spring. But drinking from it will make you drunk. Then, like Carly’s sixth hangover, you’ll remember a few of the good parts while largely forgetting the rest.