20 Things You Didn't Know About Psycho

17. Chocolate Syrup Was Used For Blood

It's not much of a secret that the vast majority of food productions mix a viscous liquid like corn syrup with red food colouring to create realistic-looking blood, but things are a little different where black-and-white filmmaking is concerned.

As a result, Hitchcock decided instead to use Bosco Chocolate Syrup to double for blood, feeling that it created a stronger and more effective contrast on camera.

Without the need to find a substance with the correct colouring, Hitch was free to basically use whatever he wished, and watching the final film, you'd never know it was actually a desert topping.