Oliver Reed as Dr. Henry Heckyl/Mr. Hype

Sunny Johnson as Coral Careen

Maia Danziger as Miss Finebum

Virgil Frye as Lt. Mack Druck - 'Il Topo'

Mel Welles as Dr. Vince Hinkle

Corinne Calvet as Pizelle Puree

Kedric Wolfe as Dr. Lew Hoo

Dick Miller as Irsil / Orson

Tony Cox as Bad William

Charles Howerton as Clutch Cooger

Jackie Coogan as Sgt. Fleacollar

Lucretia Love as Debra Kate

Herta Ware as Old Lady on a Bus

Ben Frommer as Sgt. Gurnisht Hilfn

Mickey Fox as Mrs. Fritz L. Pitzle

Catalaine Knell as Mrs. Fritz L. Pitzle

Jacque Lynn Colton as Mrs. Fran van Crisco

Lisa Zebro as Mrs. Fran van Crisco

Stan Ross as Flash Flud

Duane Thomas as Bad Williams' Ideal

Candi Brough as Terri - Tailspin Twin

Randi Brough as Toni - Tailspin Twin

Dan Sturkie as Naso Rubico, the Wino

Carin Berger as Nurse Lushtush

Merle Ann Taylor as Nurse Talltale

Edward B. Randolph as Midnight Eaglehead

Denise Hayes as Liza Rowne