The blond bombshell (of a thousand goofy faces) wrote and stars in the movie, directed by her husband, John Asher (search). (They filed for divorce last month, after six years of marriage.)
"We wanted to kill each other the entire making of the movie," says McCarthy. "As the writer, I had a really strong vision of what I wanted, and he, as the director, had his own vision, so we clashed. The next time we work together, we'll need a referee."
Hitting theaters this weekend, "Dirty Love" opens with a wailing Rebecca (McCarthy) grabbing at hookers and the homeless on Hollywood's Walk of Fame after discovering her boyfriend has cheated on her.
After recruiting a few feisty friends (Carmen Electra, Kam Heskin and Eddie Kaye Thomas), Rebecca begins a quest to find her true love, something that can happen only after a number of bizarre detours.
Some of these screechingly funny turns -- not for the squeamish -- include a crime scene-like heavy flow day in the supermarket ("Cleanup in produce!") and a nasty encounter with a man who has a fetish involving chilled bass.
"It's a true story. The guy had to be taken to the hospital because he stuck a frozen fish up there and it started to thaw," says McCarthy, who claims to know the man in question.
Asked if there was ever a moment when she thought she may be going too far, McCarthy immediately says no.
"I knew the point where people would get sick, and I didn't want to do that," she says. "I wanted to make them laugh."
McCarthy says she prefers not to write her own scripts, but she didn't have much choice.
"Unfortunately there's hardly any female screenplay writers who write comedies for female leads," she says. "So I've kind of been forced by gunpoint, if I want to continue in this career, to take matters into my own hands.
"I wanted to write something that only a guy would do or that would only be written for guys."
Going for the disgustingly funny also appealed because McCarthy is tired of the sappy roles women tend to have in romantic comedies.
"Sexy women take themselves so seriously, or the romantic girl lead is always sweet and innocent," she says. "Women get dirty. Women get naughty. They get crazy. I just wanted to be able to show it and make fun of it all."