This is about the film. For the stage musical, see Little Shop of Horrors (musical).
- Rick Moranis - Seymour Krelborn
- Ellen Greene - Audrey
- Steve Martin - Orin Scrivello, D.D.S
- Levi Stubbs - Audrey II
- Tichina Arnold - Crystal
- Michelle Weeks - Ronette
- Tisha Campbell-Martin - Chiffon
- Vincent Gardenia - Mr. Mushnik
- James Belushi - Patrick Martin
- John Candy - Wink Wilkinson
- Christopher Guest - First Customer
- Bill Murray - Arthur Denton
In September 1962, Seymour Krelborn and his colleague, Audrey, work at Mushnik's Flower Shop, lamenting they cannot escape the slums of New York City. Struggling from a lack of customers, Mr. Mushnik prompts to close the store, only for Audrey to suggest displaying an unusual plant Seymour owns. Immediately attracting a customer, Seymour explains he bought the plant, which he dubbed "Audrey II", from a Chinese flower shop during a solar eclipse. Attracting business to Mushnik's shop, the plant soon starts dying, worrying Seymour. Accidentally pricking his finger, he then discovers Audrey II needs human blood to thrive.
Audrey II continues to grow rapidly and Seymour becomes a local celebrity. Seymour soon attempts to ask Audrey out, but she turns him down because she has a date with her violent, sadistic dentist boyfriend Orin Scrivello. Despite this, Audrey is interested in Seymour, as well as dreams of marrying him and escaping Skid Row. After Seymour closes up shop, Audrey II begins to talk to Seymour, demanding more blood than Seymour can give. The plant proposes Seymour murder someone in exchange for fame and fortune: Seymour initially refuses, but agrees upon witnessing Orin slapping Audrey.
Seymour books an appointment with Orin and arms himself with a revolver: however, he cannot bring himself to use it. Orin, who abuses nitrous oxide, puts on a type of venturi mask to receive a constant flow of the gas. Accidentally breaking an intake valve and unable to remove the mask, Orin begs Seymour for help removing it as Seymour just stands there. When Orin asks Seymour what he ever did to him, Seymour replies, "Nothing, it's what you did to her." Orin dies from asphyxiation and Seymour drags his body back to Audrey II. While dismembering the body for the plant, Seymour is unknowingly spotted by Mushnik, who flees in fear.
After feeding Orin's parts to Audrey II, Seymour discovers the police investigating Orin's disappearance. Audrey, feeling guilty about wishing Orin would disappear, is comforted by Seymour and the two admit their feelings for each other. That night, Mushnik confronts Seymour, believing he murdered Orin. Threatening to turn Seymour in, Mushnik offers to let him escape in exchange for the secret to the plant's care routine. Out of options, Seymour causes Mushnik to back into Audrey II's open mouth, who then devours Mushnik.
Despite widespread success, Seymour worries about Audrey II's growth and insatiable appetite. Offered money and a contract for a botany TV show, Seymour plans to escape Skid Row with Audrey using the money, leaving the plant to starve. After Audrey accepts Seymour's marriage proposal, Audrey II catches Seymour leaving and demands another meal: Seymour agrees, but insists on meat from a butcher. While Seymour is gone, the plant calls Audrey, coaxes her into the shop and then tries to eat her. Seymour, returning in time to save Audrey, escapes the store with her. Explaining that he fed the plant to become successful and win Audrey's heart, Seymour discovers she has always liked him. Approached by an executive from a botanical company named Patrick Martin, Seymour is offered a contract to breed Audrey II and sell the saplings worldwide. Seymour then realizes he must destroy Audrey II and the plant's plans for planetary domination.
Confronting Audrey II, Seymour learns the plant is in reality an alien from outer space. Trapping Seymour, Audrey II collapses the store, attempting to kill him. Seymour, trapped under debris, grabs an exposed electrical cable and electrocutes Audrey II, causing it to explode. Leaving the destroyed shop, Seymour safely reunites with Audrey. The two wed and move to the suburbs: arriving at their new home, a smiling Audrey II bud can be seen among the flowers in their front yard.
In the original ending, after Audrey is attacked by Audrey II, Seymour rescues Audrey, who is seriously injured. Confessing to Audrey he fed Mushnik and Orin to Audrey II, Audrey requests Seymour feed her to the plant and earn the success he deserves before she dies in his arms. Seymour does so, but soon attempts to commit suicide only to be stopped by Patrick Martin. Patrick offers to reproduce and sell Audrey II as he had grown a smaller Audrey II from one of the clippings that he harvested as the smaller Audrey II smiles at him. He also warns Seymour that his consent isn't necessary as plants are considered public domain. Realizing Audrey II's plans for global domination, Seymour climbs down the roof with the resolution to destroy the plant. Returning to the shop, Seymour confronts and tries to kill Audrey II, who tears down the shop, plucks Seymour out of the rubble and eats him alive. Audrey II then spits out Seymour's glasses and laughs.
The three chorus girls appear in front of a large American flag and tell how although Audrey II buds became a worldwide consumer craze, the buds grew into an army of monstrous plants who begin to take over the Earth. Giant Audrey II plants are shown destroying cities, toppling buildings, as well as eating people. The final shot shows the U.S. Army as it attempts to fight the buds as they ascend the Statue of Liberty. An Audrey II then breaks the fourth wall to eat the audience as the camera zooms into its mouth.
- Prologue ("Little Shop of Horrors") – Chiffon, Crystal, and Ronette
- "Skid Row (Downtown)" –seymour, Audrey, Crystal, Ronette, Chiffon and Street People
- "Da-Doo" – Chiffon, Crystal, and Ronette
- "Grow for Me" – Seymour
- "Somewhere That's Green" – Audrey
- "Dentist!" – Orin, Chiffon, Crystal, and Ronette
- "Feed Me (Git It)" – Audrey II and Seymour
- "Suddenly, Seymour" – Seymour, Audrey, Chiffon, Crystal, and Ronette
- "Suppertime" – Audrey II
- "The Meek Shall Inherit" - Seymour, Crystal, Ronette and Chiffon
- "Mean Green Mother" - Audrey II
- "Sominex/Suppertime" (reprise)(alternate ending) – Audrey and Audrey II
- "Somewhere That's Green" (reprise)(alternate ending) – Audrey
- "Don't Feed the Plants"(alternate ending) – Crystal, Ronette and Chiffon