Cheerfully vulgar and outrageously camp, "The Road to Wellville" is a broad spoof of the crackpot health prescriptions preached by Dr. John Harvey Kellogg at the turn of the century in his health sanitarium in Battle Creek, Mich.

It's also too gross for comfort.

Kellogg, though quite the obsessed eccentric, was a genius of sorts. An author, inventor and surgeon, his many creations include peanut butter, the electric blanket and the corn flake — yes, he's that Kellogg.

But his health advice included several enemas a day, a stringent biological diet and complete abstinence from sex, among other impractical advice. (The real joke here is the parallel to offbeat health advice that is still being preached loudly today.)

As far as the movie is concerned, one may well wonder how much of this is true — my guess is, not much — but writer-director Alan Parker (basing the film on a novel by T. Coraghessan Boyle) is more interested in shock and broad comedy than any sort of reality. In fact, none of the actors in the movie rise above caricature, and that's obviously how Parker wanted it.

Kellogg himself is the central character, played wildly over the top by Anthony Hopkins, complete with Bugs Bunny overbite and a voice inflection that seems to be imitating John Huston. Hopkins sets the stage, and the other players attempt to follow . . . though none manage to reach quite the same height of lunacy.

Basically an ensemble piece, the bulk of the action cuts back and forth between the stories of Will Lightbody (Matthew Broderick), a recovering alcoholic with a weak stomach who has been dragged to the sanitarium by his chipper wife Eleanor (Bridget Fonda), and Charles Ossining (John Cusack), who has come to Battle Creek with his aunt's money and linked up with a con artist in hopes of becoming another cornflake tycoon.

The sanitarium is a flamboyant combination of spa, hospital and grand hotel, where Kellogg's employees take patients through laughing exercises, put them on torturous machines and give them frequent "colonic washes." "The bowels are our passage to health" Kellogg says, one of the many pithy epigrams placed throughout "The San" and spoken by him at every opportunity.

When Will and Eleanor arrive, Kellogg immediately grabs Will's tongue and gives him an on-the-spot, in-the-lobby examination, then sends him off to his room in a wheelchair, insistent that he get his first enema immediately. And despite Kellogg's anti-sex tirades, Will, who has been celibate for some time, has fantasies about his nurse, Irene Graves (Traci Lind), and the sickly Ida Muntz (Lara Flynn Boyle), whose room is across the hall. As you might expect, he is soon acting on those fantasies. And repressed Eleanor is befriended and coached by the uninhibited Virginia Cranehill (played superbly by newcomer Camryn Manheim, who delivers the film's most natural, believable performance.)

Meanwhile, George and his "partner" Goodloe Bender (Michael Lerner) set up shop with one of Kellogg's disgruntled employees, as well as Kellogg's estranged adopted son George (Dana Carvey), to create their own corn flake . . . without much success.

Parker frequently cuts back and forth between these stories at a frantic pace and with musical interludes, a device that grows old after a time. And though the film gets off to a rousing start, with a very promising first quarter, by the halfway mark it has pretty much worn out its welcome.

Despite some big laughs and the efforts of the terrific cast, the funniest scenes are flashbacks about Kellogg attempting to discipline very stubborn young George (played as a boy by Jacob Rey-nolds).

But no one ever accused Alan Parker ("Midnight Express," "Angel Heart," "Mississippi Burning," "Pink Floyd The Wall") of a light hand, and occasionally the mix of sentiment and crass farce is uneasy at best. And after awhile, it becomes apparent this is a one-joke movie . . . and the joke becomes quite thin indeed as the film progresses.

The look of the film is fabulous, however, with an incredible amount of attention paid to period detail. And Rachel Portman's music is quite enjoyable.

"The Road to Wellville" is rated R for some violence, as well as considerable nudity, sex and vulgarity, and a few profanities.