Theatrical blood

The bloodred color of iron thiocyanate can simulate the appearance of blood.

Theatrical blood, stage blood or fake blood is anything used as a substitute for blood in a theatrical or cinematic performance. For example, in the special effects industry, when a director needs to simulate an actor being shot or cut, a wide variety of chemicals and natural products can be used. The most common is red food coloring, often inside small balloons coupled with explosive devices called squibs.