Geneviève Bujold as Dr. Susan Wheeler

Michael Douglas as Dr. Mark Bellows

Elizabeth Ashley as Mrs. Emerson

Rip Torn as Dr. George

Richard Widmark as Dr. Harris

Lois Chiles as Nancy Greenly

Hari Rhodes as Dr. Morelind

Richard Doyle as Jim

Alan Haufrect as Dr. Marcus

Lance LeGault as Vince

Michael MacRae as Chief Resident

Frank Downing as Kelly

Gary Barton as Computer Technician

Betty McGuire as Nurse

Tom Selleck as Sean Murphy

Charles Siebert as Dr. Goodman

William Wintersole as Lab Technician

Ernest Anderson as First Doctor

Harry Basch as Second Doctor

Maury Cooper as Third Doctor

Joni Palmer as Dance Instructor

Joanna Kerns as Diane

Kay Cole as Sally

Tom Borut as Dr. Cowans

Philip G. Brooks as Dr. Richards

Benny Rubin as Mr. Schwartz

David Hollander as Jimmy

Dick Balduzzi as 1st Maintenance Man

Gary Bisig as 2nd Maintenance Man

Kurt Andon as 1st Cop

Wyatt Johnson as 2nd Cop

Mike Lally as Security Man

John Widlock as Norman

Duane Tucker as 1st Man in Shower

Del Hinkley as 2nd Man in Shower

Paul Ryan as 1st Technician

Michael Mann as 2nd Technician

Sarina C. Grant as Woman in Elevator

David McKnight as Man in Elevator

Gerald Benston as Anesthetist

Robert Burton as Pathology Resident

Ed Harris as Pathology Resident

Joe Bratcher as Surgical Resident

Martin Speer as Surgical Resident

Roger Newman as Surgical Resident

Paul Davidson as Surgical Resident

Amentha Dymally as Nurse

Lois Walden as Nurse

Sharron Frame as Nurse

Sue Bugden as Nurse

Susie Luner as Nurse

Vaughn Armstrong as Jefferson Institute Security Guard (uncredited)

Jason Bernard as Surgical Resident (uncredited)

Gerald Berns as Security Guard (uncredited)

Jeffrey Corazzini as Patient (uncredited)

Bob Dio as Subway Passenger (uncredited)

Philip Baker Hall as Doctor (uncredited)

Edward C. Higgins as Security Guard (uncredited)

Mary D. Mascari as Doctor (uncredited)

Gerry Vichi as Ambulance Driver (uncredited)

Nicholas Worth as Patterson Institute Chief of Security (uncredited)