We’ve all seen it in the movies. The bad guy grabs someone from behind, places a rag over the victim’s nose and mouth, and instantly the person slumps to the floor.

This isn’t exactly how anesthesia is administered in a hospital, but many people wonder if this rag trick is possible, and if so, what is the chemical on the rag?

Chloroform and ether are the two possibilities. In the mid-1800s, both of these chemicals were being used as anesthetics. Chloroform is the more common substance discussed in these cinematic knockouts but actually doesn’t work as swiftly as portrayed. It usually takes several minutes to induce a state of unconsciousness with chloroform. Chloroform also causes a lot of side effects including nausea, vomiting, and skin irritation.

Ether was discovered in the 1500s and later used as an anesthetic. It was also used to treat respiratory ailments such as asthma. Ether became popular and turned into an early party drug that people used to get high. Unfortunately, ether can’t deliver that dramatic takedown either.

Another option for the quick movie knockout involves secretly dissolving a pill in a drink. This is often referred to as “slipping a mickey” or a Mickey Finn. Spiked drinks in this sense contain Chloral hydrate dissolved in alcohol. Chloral hydrate is a sedative that is used in hospitals today, often to sedate children prior to procedures. Other modern movie knockout options are the so-called date rape drugs: GHB, Rohypnol, and ketamine.