…and vomit, and other fake and forbidden substances, just like they do in Hollywood.
When an actor portrays a character that needs to be shot, their body is rigged with small, exploding capsules called squibs. When they’re set to go off, they spew out little bits of red substance to mimic blood of course. The most commonly used fake blood in the film industry is quite simple—regular, thick corn syrup dyed a deep red hue. Before the advent of color film, directors didn’t have to worry about a realistic shade. On the black-and-white film Psycho, for instance, Alfred Hitchcock simulated blood with chocolate syrup, which had the consistency he sought.
Performers don’t really use drugs in movies where their character does drugs. First of all, that would be quite illegal (depending on the drug and the place where the movie films), and also at least a little unhealthy. On The Pineapple Express, a comedy about marijuana, prop masters did use real marijuana, although it was a specially grown batch that had all of the “active ingredient,” or the intoxicating chemical, removed. On other movie sets, oregano has been the most commonly used fake-marijuana.
Cocaine is a white powder, but on movies not just any white powder will do, especially if actors have to ingest it. Some prop masters swear by lactose powder—milk-derived sugar—which doesn’t negatively affect the human body in small doses (unless the actor is lactose intolerant). On the drug-heavy movie The Wolf of Wall Street, the fake drug was Vitamin D powder. Actor Jonah Hill was required to ingest so much of it that he was hospitalized with bronchitis for three weeks.
Pretend vomit, like real vomit, can take on a variety of colors and textures. Prop masters have known to make up batches that include stuff like oatmeal, coffee-based smoothies, baby food, tapioca, vegetable soup, and especially bananas. (When the possessed Regan in The Exorcist hurled, she hurled split pea soup.) The go-to fake-vomit base for decades was peach yogurt, but more recently Hollywood has turned to another, more accurate depiction: CGI.