Klaus Kinski as Dr. Francis Clay

Margaret Lee as Cheryl Hume

Rosalba Neri as Anne Palmieri

Jane Garret as Mara

John Karlsen as Professor Osterman

Gioia Desideri as Ruth

Giangiacomo Elia as The Gardener (as John Ely)

Monica Strebel as Nurse Helen

Fernando Cerulli as Chaffeur

Sandro Rossi as Policeman

Giulio Baraghini as Policeman

Ettore Geri as Inspector

Antonio Radaelli as Policeman

Carla Mancini as Nurse

Franco Marletta as Male Nurse

Piero Nistri as Cheryl's Husband

Daniela Di Bitonto as Patient

Enzo Spitaleri as Ruth's Husband

Marco Mariani as Male Nurse

Gilberto Galimberti as Policeman

Rosanna Braida as Patient

Lina Franchi as Nurse Killed with Scythe (uncredited)