Ronald Colman
Dr. Martin Arrowsmith
Helen Hayes
Leora Tozer Arrowsmith
Richard Bennett
Gustav Sondelius
A.E. Anson
Professor Max Gottlieb
Clarence Brooks
Dr. Oliver Marchand
Alec B. Francis
Twyford
Claude King
Dr. Tubbs
Bert Roach
Bert Tozer
Myrna Loy
Joyce Lanyon
Russell Hopton
Terry Wickett
David Landau
State Veterinarian
Lumsden Hare
Sir Robert Fairland
Erville Alderson
Pioneer (uncredited)
Ward Bond
Cop (uncredited)
Beulah Bondi
Mrs. Tozer (uncredited)
Florence Britton
Miss Twyford (uncredited)
Nora Cecil
Nurse (uncredited)
Sidney De Gray
Dr. Hesselink (uncredited)
Cyril Delevanti
Committee Member (uncredited)
Walter Downing
City Clerk (uncredited)
Gibson Gowland
Committee Member (uncredited)
Sherry Hall
Reporter (uncredited)
Theresa Harris
Native Mother (uncredited)
Raymond Hatton
Drunk (uncredited)
Charlotte Henry
Pioneer Girl (uncredited)
George Humbert
Italian Uncle (uncredited)
DeWitt Jennings
B.W. Tozer (uncredited)
Mike Lally
Reporter (uncredited)
Lillian Lawrence
West Indies Townswoman at Meeting (uncredited)
Carl M. Leviness
Ship's Passenger (uncredited)
James A. Marcus
Old Doctor (uncredited)
Eric Mayne
Dignitary at Luncheon (uncredited)
Kendall McComas
Little Johnny (uncredited)
Edmund Mortimer
Ship's Passenger (uncredited)
John Qualen
Henry Novak (uncredited)
Edward Reinach
Dignitary (uncredited)
Milton Royce
Intern (uncredited)
Harry Schultz
Bartender (uncredited)
Pat Somerset
Ship's Officer (uncredited)
Adele Watson
Mrs. Novak (uncredited)
Bobby Watson
Little Neighbor (uncredited)
Eric Wilton
Ship's Officer (uncredited)