Underground criminal Divine lives under the pseudonym "Babs Johnson" with her mentally ill, egg-loving mother Edie, delinquent son Crackers, and traveling companion Cotton. They all live together in a pink and green trailer on the outskirts of Phoenix, Maryland, in front of which can be found a gazing ball alongside a pair of eponymous plastic pink flamingos. After learning that Divine has been named "the filthiest person alive" by a tabloid paper, jealous rivals Connie and Raymond Marble set out to destroy her career but come undone in the process.
The Marbles run an "adoption clinic", which is actually a black market baby ring. They kidnap young women, have them impregnated by their manservant, Channing, and sell the babies to lesbian couples. (Channing is seen from behind, but apparently masturbates and ejaculates.) The proceeds are used to finance a network of dealers selling heroin in inner-city elementary schools. Raymond also gets money by exposing himself (with large kielbasa sausages tied to his penis) to unsuspecting women in a park and stealing their purses when they flee. The Marbles send a spy named Cookie in the guise of what Crackers thinks is a date. In one of the film's most infamous scenes, the two of them have sex while crushing a live chicken between them as Cotton looks on through a window. Cookie then informs the Marbles about Babs' real identity, her whereabouts, and her family, as well as information about her upcoming birthday party.
The Marbles send a box of human feces to Divine as a birthday present with a card addressing her as "Fatso" and proclaiming themselves "The Filthiest People Alive". Worried her title has been seized, Divine proclaims whoever sent the package must die and her two associates agree. Meanwhile, at the Marbles', Channing dresses up as Connie and Raymond, wearing Connie's clothes and imitating their earlier overheard conversations. When the Marbles return home, they catch Channing in the act and respond with outrage, firing him and locking him in a closet until they can return from their tasks and kick him out for good.
The birthday party begins as the Marbles arrive to spy on it. Divine receives an assortment of gifts, including lice shampoo, a pig's head, and an axe. Later on, they all witness a topless dancing woman with a snake and a contortionist who flexes his prolapsed anus in rhythm to the song "Surfin' Bird". One of the guests, the Egg Man, who delivers eggs to Edie daily, confesses his love for her and proposes marriage. She accepts his proposal and he carries Edie off in a wheelbarrow for a honeymoon around the egg industry. The Marbles, disgusted by the reveling, call the police, but this proves unsuccessful as Divine and the other party-goers kill the cops. Divine hacks up their bodies with the axe and the party-goers eat them.
After the party ends, Divine and Crackers head to the Marbles' house, whose address they received from the local gossip Patty Hitler, where they lick and rub everything in their house to spread their "filthiness", which excites them to the point of engaging in oral sex. Divine and Crackers find Channing locked away, but they have no sympathy for him. Once they're in the basement, Divine and Crackers use a large knife to cut the bonds and free the two captive women, then hand over the knife. The women emasculate Channing offscreen.
Meanwhile, Connie and Raymond burn Divine's beloved trailer to the ground. Upon their return home they are troubled by the behavior of their furniture. Having been "cursed" by being licked by Divine and Crackers, the furniture "rejects" the Marbles when they return home: when they try to sit, the cushions fly up, throwing them to the floor. They then find that Channing has bled to death from his castration and the two girls have escaped.
After finding the remains of the burned-out trailer, Divine and Crackers return to the Marbles' home. They take them hostage at gunpoint and return to the site of the trailer. Divine calls the local tabloid media to witness the Marbles' trial and execution, as she proclaims her belief in "filth politics":


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Blood does more than turn me on, it makes me cum. And more than the sight of it, I love the taste of it. The taste of hot, freshly killed blood...Kill everyone now! Condone first degree murder! Advocate cannibalism! Eat shit! Filth are my politics! Filth is my life! Take whatever you like.
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Divine holds a "kangaroo court", asks Cotton and Crackers for their biased testimony, and sentences the bound and gagged Marbles to death for "first-degree stupidity" and "assholism". Divine sarcastically offers them the opportunity to speak on their own behalf, but they're of course gagged and they move straight to the execution. They tie the Marbles to a tree, coating them in tar and feathers. Divine then shoots them in the head and the media leave shortly afterward, satisfied with their scoop of a "live homicide". Divine, Crackers, and Cotton talk about where to base their seat of operations next and they enthusiastically decide to relocate to Boise, Idaho, site of a homosexual scandal a few years previously.[11]
The legendary ending opens as Crackers, Cotton, and Divine walk down the street, where they spot a dog and its owner. They look at the dog excitedly and hungrily for some reason. Then the dog defecates on the sidewalk, and Divine sits down next to it. She takes the feces in her hand and puts them in her mouth, proving, as the narrator states, that she is "not only the filthiest person in the world, but is also the world's filthiest actress". She gags twice and grins at the camera.
Who do Divine and Crackers find locked away?
Channing