A Day at the Races (1937) is the seventh film starring the Marx Brothers, with Allan Jones, Maureen O'Sullivan and Margaret Dumont. Like their previous Metro-Goldwyn-Mayer feature A Night at the Opera, this film was a major hit.

Plot

The Standish Sanitarium, owned by Judy Standish (Maureen O'Sullivan), has fallen on hard times. Banker J.D. Morgan (Douglass Dumbrille), who owns a nearby racetrack and nightclub, holds the mortgage to the sanitarium and is attempting to gain control of it in order to convert the building into a casino. Judy's faithful employee Tony (Chico Marx), suggests asking financial help from the wealthy hypochondriacal patient Mrs. Emily Upjohn (Margaret Dumont). After she has been given a clean bill of health by the doctors at the Sanitarium, Mrs. Upjohn threatens to leave for treatment by Dr. Hugo Z. Hackenbush (Groucho Marx), who - and unknown to Mrs. Upjohn - is actually a horse doctor. Tony overhears Mrs. Upjohn's praise of Hackenbush and immediately tells her that Dr. Hackenbush has been hired to run the sanitarium. Mrs. Upjohn is elated and informs Judy with Dr. Hackenbush in charge she will consider helping her financially. Tony then wires Dr. Hackenbush in Florida to come and care for Mrs. Upjohn at the sanitarium. Soon, Dr. Hackenbush arrives and instantly begins insulting the sanitarium's crooked business manager Mr. Whitmore (Leonard Ceeley). Whitmore, who is Morgan's right-hand man, is immediately suspicious of Hackenbush's medical background.