First American film to credit the stunt people in the credits (first British film to do so was the James Bond film Moonraker (1979)).

The fender bender Judy causes as she crosses the street to the Bristol Hotel was added on the spur of the moment. When no stunt cars were available, Peter Bogdanovich instructed a crew member to rent two cars and make sure he got collision insurance. Then he staged the wreck before returning the battered cars.

Ryan O'Neal parodies one of his earlier performances. At the end of the movie, Judy Maxwell says, "Love means never having to say you're sorry," (a line from Love Story (1970)), to which O'Neal's character, Howard Bannister, replies, "That's the dumbest thing I ever heard."

The final chase scene, a spoof of the one from the then recent movie Bullitt (1968) which was also filmed in San Francisco, cost $1 million to shoot (a quarter of the total budget), 19 days to shoot requiring 32 stuntmen resulting in 11 minutes of screen time. The segment with the giant pane of glass alone took four or five days to film. The plate glass bit was filmed at the junction of Balboa and 23rd Avenue in San Francisco's Richmond District.

Director Peter Bogdanovich did not get permission from the city of San Francisco to drive cars down the concrete steps in Alta Plaza Park; these were badly damaged during filming and still show the scars today. Because of the damage to city property during the filming of this movie, San Francisco now requires productions to provide with its filming permit application a very detailed scene-by-scene breakdown of everything that the company is asking permission to film.

When Howard Bannister ends up at the rooftop cocktail lounge, which was under construction, it was not a set, but actually the "Starlight Roof" of the Hilton, which was being remodeled at the time. The view of San Francisco is the actual view from the room. A piano was brought up and placed in the room for the shot. Barbra Streisand sang the song live, not to a recording, because director Peter Bogdanovich wanted her singing to sound natural as she stepped down from the top of the piano.

As his part is inspired by the stuffy professor played by Cary Grant in Bringing Up Baby (1938), Ryan O'Neal met with Grant. The only advice he received was to wear silk underpants.

The long-haired blond delivery boy whose bike Judy steals is played by Kevin O'Neal, Ryan O'Neal's brother. The woman she sits next to on the plane in the final scene is Patricia O'Neal, their mother.

This film was morphed from the screen adaptation of Herman Raucher's novel, "A Glimpse of Tiger." It was to star Elliott Gould and Kim Darby and be directed by Anthony Harvey but Gould behaved erratically during production and, after four days, walked off the set. The project eventually came into the hands of Peter Bogdanovich, who, conceiving it as a remake of Howard Hawks' Bringing Up Baby (1938) switched the genders of the lead couple, making the wild, unpredictable Gould character a woman, who would be played, coincidentally, by Gould's ex-wife Barbra Streisand.

The pizza restaurant where Judy Maxwell watches pizzas being made was a real pizza restaurant at the time and remains virtually the same to this day. It's located at Bush St. on the corner of Jones.

Feature film debut of Madeline Kahn.

The lobby and pharmacy of the "Bristol Hotel" was the actual San Francisco Hilton Hotel, which was shot late at night, when it could be closed off for the shoot. The actual Mason Street entrance was also used for a couple of shots, but shot during the day. A crowd of onlookers can briefly be seen standing across the street.

A male stuntman was used to double for Barbra Streisand in the long shots of her riding the bicycle. During one hairpin turn, he fell off and broke his ankle.

One of the film's main tagline's, "A screwball comedy. Remember them?", was also the name of the short promo documentary featurette made to promote the movie.

As Judy stands outside the pizzeria watching the chef toss dough, "Santa Lucia" can faintly be heard coming from inside. The singer is Peter Bogdanovich.

The movie premiered at the 6,000 seat Radio City Music Hall Theater in New York City in 1972. The film's first 2 weekends broke the house record that had stood since 1933.

It is widely thought that the character of the obnoxious "Hugh Simon", played by Kenneth Mars, is an outrageous parody of the film and drama critic John Simon, who had a considerable media profile at the time, was notorious for his rudeness and often deeply personal and insulting remarks about the people whose work he reviewed, and had been grossly defamatory on TV about Peter Bogdanovich's acclaimed previous film, "The Last Picture Show" and in print about Barbra Streisand.

Sylvester Stallone was an extra in this film. However, he is not seen very clearly in his scenes, as he is walking far away in the background.

In the parade in Chinatown with the Chinese dragon, the music the band is playing is "La Cucaracha" ("The Cockroach"), a Mexican tune.

Ryan O'Neal's line in the airport terminal ("Judy? Judy? Judy.") is an homage to Cary Grant who starred in Bringing Up Baby (1938), the film that inspired this movie. Although Grant never said "Judy, Judy, Judy" in any film, the line was constantly attributed to him.

Liam Dunn was primarily a casting director before Peter Bogdanovich offered him the role of Judge Maxwell.

Barbra Streisand's role was a Carole Lombard-type character. Director Peter Bogdanovich once said that Streisand was "the first person we've had on the screen like Carole Lombard". When writing, Streisand's character was fashioned in the mold of Lombard.

The stuntman portraying the gentleman sitting in the back seat of the convertible during the chase scene was knocked cold when his head hit the awning on the dock just before the car went off the dock.

Much of Hugh Simon's "foreign" language was actor Kenneth Mars' made-up interpretation of Serbo-Croatian, director Peter Bogdanovich's native language.

The movie is ranked at No. #68 on the American Film Institute's "100 Years... 100 Passions" film list. It is also No. #61 on the AFI's "100 Greatest Comedies" movie list.

Director Peter Bogdanovich had Ryan O'Neal and Barbra Streisand watch The Lady Eve (1941) to prepare for this film.

The picture was the third highest grossing movie of the year on the North American continent behind only The Godfather (1972) and The Poseidon Adventure (1972). The film was re-issued in the same territory in 1973 and added even more boffo biz to its coffers.

When Judy Maxwell first enters the Bristol Hotel, a piano version of Cole Porter's "Anything Goes" can be heard in the background. Porter also wrote "You're The Top," the song that begins and ends the movie. When Howard and Judy are left alone talking in the Bristol Ballroom after the convention, "Night & Day" can be heard in the background, another song by Cole Porter. It is Ironic that Cary Grant, the Actor to whom it is said this film is a Homage to, played Cole Porter in his Biographical Movie, "Night & Day."

When Judy Maxwell is seen outside on the ledge of the hotel, it was filmed on a sound stage in Burbank, however, the long shot of Judy hanging on the ledge is actually a stunt woman who was hired to dangle from a building in Westwood, California.

Kenneth Mars ad-libbed almost all of his dialogue.

During the big chase scene, a man is chased by a large number of trashcans. This is a homage to Buster Keaton's short "Seven Chances".

An early film role of actor Randy Quaid playing Professor Hosquith. Quaid had previously worked with director Peter Bogdanovich in his debut movie in The Last Picture Show (1971).

When Judy tells the woman on the plane that the new school Judy's going to attend is a small college but that there are those who love it, she's actually quoting from Daniel Webster's famous argument to the Supreme Court in the Dartmouth College case, circa 1820.

Judy's Majors: (1) Political Science, Colorado State; (2) Advanced Geology, Wellesley; (3) Musical Appreciation, Bennington; (4) Comp Lit, Northwestern University; (5) Archeology, Tuskegee Institute; (6) General Semantics, U of Chicago; (7) Veterinary Medicine, Texas A & M; (8) Chemistry, No school given; (9) New Math, Mt Holyoke.

During the chase scene the large black limo loses its hood during a hard turn. It was an accident but kept in the film.

In the scene where the cars drive into the water, the stunt man who is standing up in the Cadillac convertible suffered a severe concussion when he hit the water. He could not recall doing the stunt for years afterwards.

Artie Butler did not write a score for this film. The music was actually previously recorded tunes from the Warner Brothers library which Mr. Butler arranged throughout the film to sound like "elevator music" throughout the film. He did record the songs sung by Streisand for the film, but nothing more.

At Frederick Larrabee's mansion, except for the stained glass windows duplicating the actual San Francisco residence (at 2018 California Street), the ultra-modern interior is completely decorated in black and white, including the butler and maid. This was done to focus attention on the colorfully dressed guests at the party.

The film's title is taken from the famous "What's Up, Doc?" catch-phrase regularly spoken by Bugs Bunny, the movie being a partial homage to the character and his Warner Bros. cartoons. Such a Warner Brothers short animation, One Froggy Evening (1955), is actually excerpted at the start of the movie.

The name of the curvy street that the car chase moves down is Lombard Street, called "the crookedest street in the world". It has eight hairpin turns.

According to Peter Bogdanovich on the dvd commentary, the line " I would like to say I love your hair", spoken by Kenneth Mars was improvised.

The book which Eunice is reading in bed and which she subsequently tosses away in disgust is 'The Sensuous Woman' by "J", a best-seller at the time, depicting in very graphic detail various sexual techniques from a woman's viewpoint.

The view that Judy Maxwell sees below when she is outside the hotel on the ledge is looking down from the St. Francis Hotel. The old Stewart Hotel (across the street at 353 Geary) is clearly visible.

The closing sequence features Ryan O'Neal's only on-screen singing, in a duet with Barbra Streisand in "You're The Top".

The movie was inspired by the Hollywood screwball comedies of the 1930s and 1940s which had starred the likes of such actors as Cary Grant, Katharine Hepburn and Carole Lombard and been directed by such directors as Howard Hawks and Frank Capra. The movie was also inspired by such silent comedies such as those made by Mack Sennett, the Keystone Kops and Harold Lloyd with Ryan O'Neal's mannerisms in the movie being based on Lloyd. The Marx Brothers were also an inspiration for the film.

The tune that is whistled by Barbra Streisand outside the pharmacy was George Gershwin's "Someone to Watch over Me". Streisand also sings in the movie the Cole Porter classic "You're the Top" and about half of "As Time Goes By" from another Warner Brothers movie, the classic Casablanca (1942). In the film, in one scene, Streisand also impersonates the star of that film, Humphrey Bogart.

The notion of a hand opening the cover of a book for the opening credits stemmed from Howard Hawks' Red River (1948), a personal favorite of director Peter Bogdanovich.

The movie featured a number of actors who appeared in the comedies of Mel Brooks. These included Liam Dunn, Madeline Kahn, John Hillerman and Kenneth Mars.

During the bailiff's opening instructions to the court the judge's name is included - even if it is difficult to discern - spoiling that he is related to Judy.

By 2008 the San Francisco Hilton did not have a room 1717.

The background music heard during the American Musicologists' banquet were themes from Thoinot Arbeau's Orchésographie unconventionally played on a sitar and Hammond organ. Moreover, the name of the tune that the Chinese marching band was unconventionally playing on German glockenspiels was the Mexican tune of "La Cucaracha".

Two years after this film Kenneth Mars, Madeline Kahn and Liam Dunn would appear together in Young Frankenstein (1974). In both films Mars would play a nemesis of the male lead while speaking in a foreign accent and Kahn would play an overbearing, jilted fiancé.

Barbra Streisand's zany performance is an homage to the great comediennes of the 1930s like Carole Lombard, Marion Davies, Jean Arthur, and Irene Dunne.

The film is an homage to Bugs Bunny as well as the screwball comedies of the 1930s, particularly Bringing Up Baby (1938).

Adjusted for inflation to 2021 prices (and not counting the damage to the Alta Plaza Park steps), the total cost of damages came to $127,667.38. One might note that the stated cost of a VW Beetle in 1972 was $2,500.

Cole Porter's "You're the Top," performed by Barbra Streisand and Ryan O'Neal in this Peter Bogdanovich film, would be reprised by their co-star Madeline Kahn three years later, with Burt Reynolds, in Bogdanovich's live-sung Cole Porter musical At Long Last Love (1975).

On the day the scene in the courtroom was filmed director John Ford was on the set.

Three songs from Cole Porter's musical "Anything Goes" are featured in the movie. They are "Anything Goes," "You're the Top" and "I Get a Kick Out of You." An unabashed fan of Porter's music, director Peter Bogdanovich would, three years later, create At Long Last Love (1975), a full-fledged movie musical that stemmed from the composer's prodigious song catalogue.

The tune being whistled in the scene when Judy crosses the street into the hotel is the chorus of "Funiculi, Funicula".

The muzak played in the hallways of the hotel includes "Please Don't Talk About Me When I'm Gone" and "Crazy Rhythm." The former is sung by a frog in a Warner Bros. Looney Tunes cartoon.

While making a phone call in the hotel lobby, Judy Maxwell (Barbra Streisand) steals some food from a waiter's tray. This food is two carrots - just what Bugs Bunny would have picked.

Ryan O'Neal's character Howard Bannister is named for Bogdanovic's favorite director Howard Hawkes.

The Bugs Bunny's reference in the title "What's Up, Doc?" wasn't understood in Spain for its Spanish title, causing that it was the literal "¿Qué me pasa, doctor?" instead Bugs Bunny's real-translated quote "¿Qué hay de nuevo, viejo?".

Kenneth Mars ad-libbed almost all of his lines which at first drove director Peter Bogdonvich crazy. But after watching the daily takes, he let Mars continue with his wild ad-libbs.

As Howard stands in front of the TWA flight board (near the end of the movie), a sign indicates there will be no announcements of arrivals or departures, but in fact a departure announcement is audible moments later.

Four actors in this film, appeared together one year later, in "Paper Moon". They are Ryan O'Neal, Madeline Khan, John Hillerman, and Randy Quaid.

When Howard and Judy are in the hotel drugstore, Howard is tugging on Judy's hands to get free of her. When he pulls himself free he falls backwards and a shelf of Alka Seltzer falls on him. The stuffed animals that fall on him are from a box held above the camera and dumped on him to look like everything on top of the self fell off too. (Rev. DVD "The Making of What's Up Doc."

This was only the second ever movie to have the song "As Time Goes By" sung by one of the film's stars.

While trying to get away from Judy at the escalators, Howard's jacket is torn right up the back. The exact same thing happened to Cary Grant's character in 'Bringing Up, Baby.'

Mrs. Van Hoskins is seen wearing the latest in early 70's fashion: Hot Pants. The shortie shorts were all the rage for a few brief seconds and even had a perfume named after them.

It is obvious the Courtroom Scene is An Homage to Abbott & Costello, and, their play-on-words-type Routines, especially, the Ryan O'Neal Explanation to the Judge of what had happened and the Wife, Fiance, Eunice, Burnie, etc., similarity to the Who's On First? Routine. The A&C Homage is even more obvious in the interaction between Ryan O'Neal, Kenneth Mars, and Liam Dunn Hugh/You, You're Me/No, I'm Hugh (You) exchange Fodder/Father, Mudder/Mother Routine and the likes.

John Hillerman, who played hotel manager Kaltenborn later spent ten years on Magnum, P.I. as estate manager Higgins.

The San Francisco Hilton, which stood in for the Hotel Bristol, has always had a high end rooftop bar and restaurant, known for its views of the city. The present incarnation, "Cityscape," is doing business as of 2021. However, "Top of the Mark" at the Mark Hopkins on Nob Hill, still has the better view, as it always has.

Ryan O'Neal's cummerbund and bow tie are the same plaid pattern as the ubiquitous overnight bags: Royal Stewart.

The title "What's Up Doc" is a quote that often appeared in Bugs Bunny Cartoons (one of which is titled What's Up Doc? (1950)) and concludes with a scene from the cartoon. The movie contains many elements from the Bugs Bunny Cartoon Series. It begins with the main character hungry. and plotting to sneak food to eat. The main character gets sidetracked by becoming the foil for his/her costar, where he/she using his/her intelligence to talk rings around the foil. The main character insinuates him/herself into a situation by pretending to be someone else. He/She get's into various slapstick situation and a chase scenes where everybody gets hurt except for the main character.

The scene where Judy and Howard steal the VW bug, you can see several of the stunt performers wearing white sneakers.

The film's opening prologue read: "Once upon a time there was a plaid overnight case . . . ".

The hotel gift shop (actually the San Francisco Hilton) has items unique to the era which have all but disappeared now (2021) such as color souvenir slides, camera film, portable radios, and a manually operated cash register. Alka Seltzer and Bayer aspirin are still in use as of 2021.

Included among the American Film Institute's 2002 list of the top 100 America's Greatest Love Stories movies.

The opening and closing scenes were filmed at San Francisco International Airport, in what was then the TWA terminal. At the time, TWA had a film liaison office located at LAX which worked with production companies almost exclusively. The one notable exception was the film "Bullitt," which took advantage of the airline hubs of PSA and Pan Am being located at SFO.

Madeline Kahn and Peter Bogdonavich would work together again in the 1975 film musical, "At Long Last, Love!" Unfortunately, it was not viewed as a good movie by just about every critic there was.

Jewel thief Sorrel Brooke would go on to play another crafty, conniving type, Boss Hogg on TV's "The Dukes of Hazzard."

As Ryan O' Neal enters the banquet hall, an early music piece can be heard, featuring the forerunner of today's recorder.

Kevin O'Neal had an earlier brush with the law, but as a juvenile delinquent in 1966. He appeared in an episode of TV's popular Perry Mason as an apprentice car thief in an Oliver Twist-like gang run by Victor Buono. "The Case of the Twice Told Twist" was also the only episode filmed in color.

The scene where Ryan O'Neal unexpectedly encounters Barbra Streisand in his hotel bathtub might be a humorous nod to the James Bond film Dr. No, where Bond encounters Sylvia Trench playing golf in his flat. Interestingly, that actress's actual first name is Eunice.

Patricia O'Neal: The mother of Ryan O'Neal (one of the film's co-leads) as a Lady on the Plane at the end of the picture.

Kevin O'Neal: The brother of Ryan O'Neal (one of the film's co-leads) as a Delivery Boy.

The end of the car chase shows many characters swimming in San Francisco Bay except for the movie's two leads who are floating on water in a Volkswagen Beetle. The car floating was a parody of the VW's ability to float on water which had been a staple of its advertising in recent years. The make and model had also been popularized in the then recent movie The Love Bug (1968). The 1968 musical film "Chitty Chitty Bang Bang" also showed an actual floating car, but not a VW.

The four bags contain: a) Igneous rocks with musical properties belonging to Dr. Howard Bannister, b) Government papers belonging to Mr. Smith, c) Jewels belonging to Mrs. Van Hoskins and d) Clothing and a dictionary belonging to Judy Maxwell.

At one point, Ryan O'Neal yells out, 'for Pete's sake' as Barbara Streisand was in a movie called "For Pete's Sake".

The $20,000 music research grant Howard is eventually awarded is equal to over $130,000 in 2021 dollars.