A deliberate affront to good taste and conventional notions of feminine hygiene: That’s how to describe both the heroine of and the bestselling 2008 German novel Feuchtgebiete by Charlotte Roche, who claims it was inspired by her messy upbringing. And I mean messy. The film’s first sequence begins with a suggestion of ripe teen flesh, then follows 18-year-old skateboarder Helen (Carla Juri) into the world’s dirtiest restroom. There, she cheerfully explains, she likes to culture her rich microbial “pussy flora” instead of hovering over the rim, as a more prim Fraulein would do. Her methods—and those of director David Wnendt—are a calculated gross-out; and the scene sets the tenor for the rest of this amusingly filthy film.

Flashbacks soon explicate her hygienic revolt. Helen was raised by a neat-freak mother who turned out to be a monster. (“Don’t trust anyone,” she hisses at 8-year-old Helen after one particularly painful lesson.) Helen’s blithe, no-boundaries narration leads us through comic episodes from her upbringing, as girlish trust and innocence give way to corporeal revolution during adolescence. Anything that polite company won’t mention becomes Helen’s favorite topic: hemorrhoids, zits, pus, B.O., body hair, menstrual blood . . . you name it. Her epic catalogue of bodily obsessions is lighthearted; she’s bringing shame only upon herself (well, and her mother). This mortification finally leads her, by way of a shaving accident, to the hospital, where handsome male nurse Robin (Christoph Letkowski) is made to hear more of Helen’s tall tales. Maybe she’s flirting, maybe she’s nuts, but Robin is having problems with his elegant, odorless girlfriend (also a nurse), so he listens—which only encourages Helen’s provocations.

The Swiss actress Juri gamely embodies Helen’s outrageousness, showing almost every centimeter of her body without vanity. Wnendt has no option but to steer the camera away from Roche’s ripest scenes (and Juri’s ripest places); though the frequent flashbacks and lurid lighting suggest he’s hiding more than Helen’s anatomy. For all the film’s transgressive shocks, you begin to realize this is vulgarity with an agenda more personal than political. It’s all about Helen’s mom (purse-mouthed Meret Becker) and family, not Germany as a whole.

What’s Roche after, then? She became famous early as a TV host (something like an MTV VJ), and once caused a national scandal by refusing to shave her armpits. A latecomer to feminism and what’s now called “reclaiming the body,” she’s an attractive woman accustomed to the bargain of being primped and powdered for the TV lights. To have a showbiz career, she had to look good. Though the book stops short of social critique, Wetlands is partly her attack on the beauty industry—which is why the novel struck such a chord in Europe. The same ideas of normalizing the natural female body have been around for decades in feminist circles; and you have only to visit websites like Jezebel.com to read discussions of equal candor, free of squeamishness, about the tyranny of grooming and beauty standards.

For all its “Eeeew!” moments (one involving a stuck tampon), there’s something liberating about Helen’s taboo-breaking. You can’t imagine an American actress or movie so gleefully determined to offend. Wetlands isn’t particularly deep, and it ends in a rushed heap of melodrama, but Helen is a rare creature at the cinema these days: a woman who dares not to behave. Opens Fri., Oct. 10 at Sundance Cinemas. Not rated. 109 minutes.

bmiller@seattleweekly.com