How Does Chloroform Work?

Can Chloroform Really Knock You out Instantly?

You’ve seen it in movies; someone puts a chloroform soaked rag to another person’s face and they pass out immediately. Does it really work like that in real life? And if so, how? The following four answers to these questions are the best on the internet.


Using chloroform to knock someone out in a matter of seconds is entirely fiction. Chloroform is basically an anesthetic–but one that is no longer used due to the fact that it can seriously damage your liver and heart. Even with perfect dosing, it would take at least 5 minutes of breathing it to knock someone unconscious.

There are two parts to explaining how it works:
Chloroform is a volatile liquid. This means that it wants to evaporate into a gas very quickly (and thus you inhale it). It’s also lipid-soluble, which means it likes to dissolve in fats. Ever try and add water and oil together? They don’t mix. But if you try and mix different oils together, they mix quite well. Your brain’s structure has a very high concentration of fats and thus chloroform likes to dissolve there better than most other places in your body.

When in the brain, it activates something called a GABA receptor. These receptors are basically off-switches for neurons. When chloroform attaches to a GABA receptor, you can think of it as turning off a light switch. When enough light switches get turned off in the right areas of the brain–boom– lights out.


I’m an anaesthetist. Chloroform works similarly to other volatile anaesthetic agents. We think it works through potentiation of the GABA-A receptor (gamma amino butyric acid). The activation of this receptor leads to central nervous system inhibition as a result of chloride moving through the channel.

Volatile anaesthetic drugs (chloroform, halothane, enflurane, isolfurane, methoxyflurane, sevoflurane, desflurane) all work by inhibiting the CNS.

They do not work as quickly as tv and movies will have you believe but there are tricks anaesthetists can employ to sped things up. The rate at which it takes effect depends on the concentration inhaled and regional blood flow (ie to the lungs). Respiratory rate and comorbidities will also alter uptake as will heart disease (right to left shunt slows inhaled anaesthetic rate of effect).
Chloroform is not used clinically for anaesthesia any longer.


I actually have experience in being knocked out with chloroform. When I was 9 they had to remove my tonsils and I lived in a country where chloroform for small children was still used sometimes. Normally they wouldn’t have knocked me out and only sedated for tonsil removal, but because I had some other health issues they thought it would be safer.

All I remember is that I was held down and a nurse or doctor put the chloroform gauze on my mouth and nose and told me to breath. I still remember the smell of it and panicking and I remember that I kept asking just “stop for a minute, just a minute please” and I remember them taking it away for a second and than putting it back and than nothing until I woke up. So it’s definitely not a very quick knock out solution.


I was researching fast acting anesthetics, sedatives, and tranquilizers a little while back. From what I saw the fastest acting are large opioid doses.
My GF who is a nurse corroborated that, large heroin doses will make you pass TFO (within a minute) but is super dangerous. She said the rule was the faster acting it is, the more dangerous it is, with safe in the 1-5min mark.

Also, I know there are some muscle blockers, artificial and natural, that are almost instantaneous: V series nerve gases, botulinum toxin, the now famous Novichok, etc, (side effects–tachycardia, diaphragm paralysis…) And surprise, VX is being brought back for medicinal use.

Also, somatic-nerve-blockers/paralytics would allow your autonomic nervous system to still function but you would be unfeeling and immobile. These alone are not good for surgery, as its better to be asleep than awake in your own little horror movie, but are administered alongside sedatives to prevent movement.


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