I'm imagining the sleep equivalent of words like aphrodisiac, appetiser, etc.

For example:

Oysters are an aphrodisiac

Hot drinks are a {thing that makes one sleepy}

thesaurus.com doesn't give anything which leads to a suitable noun.


Most contemporary words have already been given, though 'hypnotic' is still used in pharmacology (as when distinguishing sleep-producing effects from sedation); the rest of these words are obscure.

  • hypnotic : a drug which produces sleep (i.e. sedative)
  • dwale : a stupefying or soporific drink (often specifically Belladonna) [TFD]
  • sopient : a soporific agent (medical) [OED]
  • somnifacient a drug or other agent that induces sleep.
  • somniferic : a soporific [seemingly conflated as another form of the adj somniferous, but cited as an obsolete noun by OED]
  • somnificator : a person who induces sleep [OED, rare]
  • somnivolency : a thing intended as a soporific (pl. somnivolencies) [OED, rare; a somnivolent is also one who desires] to sleep
  • somnoriferous/somnorific : adj. soporific, as said of an agent [OED, obs]
  • soporative : obs form of soporific [OED]

And a few more adjectives, since they can be easily made to refer to such a thing:

somniculous, somnific, somnifying, soporous,

  • This was most useful for me, given what I was trying to express. Thanks! – TSwire Dec 3 '14 at 1:59
  • @RenaissanceProgrammer: good call on the cultural reference, but it's on the wrong side of the concept in question. "The Itis" is really a synonym for the state of sleepiness, while the question asked for the general name of agents which cause this state. While ribs or turkey would be a specific example, the general class of sleep-promoting food might fall under something already mentioned, such as soporific. – chronometric Apr 17 '15 at 4:07
  • @TwoSheds thanks for considering my suggestion. I rebuttal your statement with: I don't think "the itis" is really a synonym for the state of sleepiness because it is only brought on by consumption of said specific examples. One wouldn't say they have "the itis" after a long days work, therefore, I believe "the itis" is a cause, just like not everyone, nor every time, that you eat ribs or turkey, do you feel sleepy. Only in cases where one has contracted "the itis" does sleepiness start to incur. :-) – RenaissanceProgrammer Apr 17 '15 at 16:12
  • Yes, this is a good call again. Calling it a synonym is not necessarily precise: it's an example of a state of sleepiness, so is only a synonym in both directions if the causation meets criteria. But the point about it being on the wrong side of cause/effect still stands ^^ – chronometric Mar 18 '17 at 4:04

Soporific, or soporiferous:

  • Inducing or tending to induce sleep.
  • Drowsy.


  • The professor’s boring speech was soporific and had everyone in the audience yawning.

  • Because of the medicine’s soporific properties, the doctor told me to only take it at bedtime.

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    The word is adjectival in form, but is often used as a noun to mean a soporific medicine, as in "She prescribed him a single dose of a potent soporific." – Brian Donovan Nov 30 '14 at 20:30
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    Yep, as soon as I saw the question I said "soporific". I think it's fairly well known and understood. – Hot Licks Nov 30 '14 at 21:55
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    Used in Beatrix Potter - The Flopsy Bunnies. – user60295 Nov 30 '14 at 23:00
  • Like this answer? – tox123 Nov 30 '14 at 23:45
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    @FrancisDavey Yes, it isn't used very much in real life. – user60295 Dec 1 '14 at 19:12

'Sedative' is a word for a thing (substance, pill, medicine, drug) that makes one sleepy, because it induces (or tends to induce) sleep.

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    It also works for non-medications, like "Dr. Slocombe's lecture on the sociopolitical implications of foot fungus is an effective sedative." – fluffy Nov 30 '14 at 23:22
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    Sedation is the reduction of irritability or agitation. A sedative does not necessarily make you sleepy. – Rudy Velthuis Dec 1 '14 at 14:26
  • Depressant is what came to mind, as in the opposite of a stimulant (like caffeine) that keeps you awake, a depressant makes you tired. – Xen2050 Dec 3 '14 at 14:24

You might like to consider

Dormitive - From Websters - A substance that causes sleep; a soporific.
Dormifacient - (Medical Term) That which brings about sleep or aids in attaining sleep; "a dormifacient agent".


Since you appear to be looking for a noun, I would say narcoleptic is your word.

  • This seems a good answer to the question. thefreedictionary.com/narcoleptic: a soporific drug that produces an uncontrollable desire to sleep. – Patrick Wood Nov 30 '14 at 22:17
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    IMO, "narcoleptic" is much stronger than just "makes you sleepy". "Hypnotic" or "soporific" are the better choices. – Rudy Velthuis Dec 1 '14 at 14:31
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    Use this one with caution: narcoleptic more often describes a person afflicted with narcolepsy. Such a person is prone to falling asleep, but a narcoleptic person doesn't cause anyone to feel sleepy. Without clarification, this could easily lead to confusion. – talrnu Dec 1 '14 at 18:57

One possibility is narcotic:

1 a : a drug (as opium or morphine) that in moderate doses dulls the senses, relieves pain, and induces profound sleep but in excessive doses causes stupor, coma, or convulsions

(Definition from merriam-webster.com)

  • narcotic would not apply in this case, although narcotics do induce sleep sometimes, they are more to be used as extreme pain killers. – tox123 Nov 30 '14 at 23:48
  • @x-x - Agreed, it's not the go-to choice, for the reason you stated; I included it here for the sake of completeness. – Erik Kowal Nov 30 '14 at 23:59
  • also for the sake of completeness: thefreedictionary.com/hypnotic – Anentropic Dec 1 '14 at 0:18
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    @x-x the fact that the word "narcotic" refers to a class of drugs which are primarily employed today as pain killers does not at all obviate the fact that the older meaning of the adjective "narcotic" -- after which that class of drugs was (perhaps mistakenly) named -- is, quite literally, "sleep-inducing". From the Greek root 'narkóō'. – Codeswitcher Dec 1 '14 at 21:00
  • @Codeswitcher I was not aware of the roots, only of the current use of the word. – tox123 Dec 2 '14 at 0:29

If you want a modern, neologian spin, I'd invent with "hybernetic" or "torporant" ...

"He imbibed a noxious hybernetic and could nigh be shocked to for days."

"The liquor, a decided torporant, reduced him to felinity within minutes."

~ me

PS — these ain't in the dictionary... not yet anyway. But what is English if not a neologian's frolickeria?

  • 1
    Neologician or novovocabulist? – Jim Reynolds Feb 5 '15 at 3:43

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