Gravis Mushnick (Mel Welles) owns a florist shop with two employees, the nerdy Seymour Krelborn (Jonathan Haze) and the sweet Audrey Fulquard (Jackie Joseph). The shop gets little business on Skid Row and Mushnick is a tightwad. When Seymour fouls up an order for a sadistic dentist named Doctor Phoebus Farb (John Herman Shaner), Seymour is about to be fired, but he tells his boss about a special plant he grew from seeds purchased from a Japanese gardener on Central Avenue. He calls the plant Audrey Junior, which pleases Audrey.

He brings in a sickly, strange potted plant, but Mushnick is not impressed and gives Seymour one week to revive it. When Seymour accidentally pricks his finger, he finds that the plant likes human blood. Feeding off Seymour, it grows and attracts curious customers. It learns to speak (John Shaner again) and demands more blood. Seymour is becoming anemic. When he throws a rock out of frustration, he knocks out a man who falls under a train and is killed. He decides to feed the man to Audrey Junior. Mushnick finds out, but the plant is attracting so much business that he decides not to call the police.

Seymour figures out his boss is on to him. Seymour goes to the dentist, Doctor Farb, who attacks him for ruining his flower order. Defending himself, Seymour kills him and feeds him to the plant as well. Police Sergeant Joe Fink (Wally Campo) and Officer Frank Stoolie (Jack Warford, who are parodies of Joe Friday and Frank Smith of Dragnet, begin to investigate. Audrey Junior is now several feet tall and budding. Seymour and the real Audrey are becoming close. When they go out on a date, Mushnick stays to guard the shop and a robber comes in. Guess what happens to him. The plant hypnotizes Seymour, who walks the streets and knocks out a hooker and feeds her to the plant too.

The police attend a celebration at the shop to honor Seymour and observe the plant’s budding. The buds have the faces of everyone killed and Seymour runs away, pursued by the cops, but he gets away. Thinking his life is ruined, Seymour climbs into Audrey Junior’s maw with a kitchen knife to kill it. That evening, the plant begins to wither and die. A bud opens with Seymour’s face just as the plant droops and perishes.

It is not stated whether Audrey Junior is an alien, but in the 1986 remake, Audrey claims to be a mean green mother from outer space. This version was made by Roger Corman because he had sets still standing from his previous film, A Bucket of Blood, on which he had paid for two more days. The story, written by Charles B. Griffith, may have been inspired by Green Thoughts, a 1932 story by John Collier, or Arthur C. Clarke’s 1956 story, The Reluctant Orchid, which was in turn inspired by H.G. Wells’ 1905 story The Flowering of the Strange Orchid. It was made for about $22,000 in two and a half days.

There is a scene with Jack Nicholson as a masochistic patient of the sadistic dentist which has nothing to do with the story, really, but helped to make it a cult favorite. There was an off-Broadway musical, a 1986 film based on that, and a 2003 Broadway revival. Sally Kellerman helped Corman and Griffith write it. She was a waitress at a diner where they were eating, heard them arguing about the script, and sat down to help. It was shot by two cameras like sit-coms are today, using winos who were paid in money for wine and railroad crews paid in Scotch. The train running over the man was actually backing away from him and the shot was run backwards.

The score was used for seven Corman films. Because he thought it would be a failure, Corman did not copywrite it and it was always in public domain. This, added to word-of-mouth, ensured its popularity. Needing to shoot a quick bridge between two scenes, Corman found a nice shot of the moon and cut it in. Later, there appeared an eight-page magazine article on the symbolism of the moon in Little Shop of Horrors. And now for something completely different.