Doctor Hugo Hackenbush, Tony, and Stuffy try and save Judy's sanitarium by winning a big race with a finicky horse owned by Judy's boyfriend Gil. There are a few problems. Hackenbush, who was recently put in charge of the sanitarium, isn't really a doctor, he's a veterinarian.
Groucho Marx
Chico Marx
Harpo Marx
Allan Jones
Maureen O'Sullivan
Margaret Dumont