Peter O'Toole as Dr. Harry Wolper

Mariel Hemingway as Meli

Vincent Spano as Boris Lafkin

Virginia Madsen as Barbara Spencer

David Ogden Stiers as Dr. Sid Kullenbeck

John Dehner as Paul

Karen Kopins as Lucy Wolper

Kenneth Tigar as Pavlo

Elsa Raven as Mrs. Mallory

Lee Kessler as Mrs. Pruitt

Rance Howard as Mr. Spencer

Ellen Geer as Mrs. Spencer

Ian Wolfe as Prof. Brauer

Mike Jolly as Boom-Boom

Burton Collins as Lyman

Judith Hansen as Karen

Doug Cox as Arthur

Anthony Peck as Norman

Crawford Binion as Fred

Byrne Piven as Krauss

Vincent Cobb as Hamberg

Gary Bayer as Bovi

Jordan Charney as Dr. Whitaker

William Bassett as Dr. Sutter

Sandy Ignon as Dr. Franklin

Jeff Corey as Dean Harrington

Michael McGrady as Larry

Eve McVeagh as Woman with Monkey

Al Fann as Guard

Michael Greene as Guard

James Murray as Martin Goodwin (uncredited)