Let’s say I have a time machine and I travel back to medieval Europe. I befriend a girl and she needs my help to save the business of her mother: a restaurant, inn, tavern, etc.

I travel back to the present and now I need to bring addictive substance(s) and add it/them to the food. Which chemical(s) will best cause customers to become addicted to the food from this business?

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    $\begingroup$ Caffeine and sugar are your sure winners. I don't know about adding it to the food--better just to introduce new stuff with it in there. Like Cola or coffee or something $\endgroup$ – Erin Thursby Apr 17 '17 at 18:25
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    $\begingroup$ This is a loaded question. You could easily provide something to make the food taste the best without resorting to dirty tactics. Or just give them some aluminum and let them be rich $\endgroup$ – Andrey Apr 17 '17 at 21:14
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    $\begingroup$ Do you mean "addicted" in the literal/medical sense, or the colloquial one? $\endgroup$ – sumelic Apr 18 '17 at 1:25
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    $\begingroup$ For what reason you want customers to be addicted? Increase popularity? Increase income? Blackmail customer(s) ? Different targets - different ways. $\endgroup$ – ADS Apr 18 '17 at 6:50
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    $\begingroup$ I think you all are overestimating the accusation of witchcraft. Step away from that trope! $\endgroup$ – Mazel Apr 18 '17 at 14:54

15 Answers 15


I'm going to suggest the chemical route.

Anything listed that doesn't seem to have a high physical dependency would just be used as classical conditioning and subconscious, psychological dependence would be created through the means of an associated enjoyment or other observed benefit/gain.

Opiates - Fentanyl is very strong and very concentrated so carrying/transporting a lot wouldn't be an issue (like sugar or caffeine) and I think this is to your advantage. Overdose might be an issue but just dose lightly. People generally consume food proportional to their weight and that's convenient and relative to the dose they could handle. Opium was really popular in the past so you'd probably already have some customers waiting, begging, fiending, inconsolably dependent.

Or a widely tolerated anti-depressant such as Wellbutrin/Bupropion

Or a benzodiazepine like Xanax or Valium

Or marijuana: munchies

Or Viagra

Or MDMA/Molly/Ecstasy: so people have fun during and after their inn visit (Pavlov's dogs)

Or an antibiotic: apple a day at Pete's keeps syphilis away

Or LSD: frequent microdosing for increased creative productivity

Or mushrooms/natural hallucinogens: but beware with this one, you might catch people talking to burning bushes out back or claiming witchcraft

Personally, though, I think you'd get the most addiction and withdrawal out of the opiates. Plus, you can just grow and process some poppies if you run out since you're in medieval Europe anyway and you can help encourage trade relations with neighboring societies. Maybe your friend can franchise her inn.

News from Jan, 2016 - "China’s Food and Drug Administration busted thirty five restaurants this week for adding poppies and ground poppy powder to dishes in the apparent hope the opiates induced repeat customers." Fascinating.

"The spice must flow" - Dune

  • $\begingroup$ MDMA, cannabis, LSD are below alcohol on the dependency (and harm) graph. Antibiotics aren't generally psychoactive (maybe if you take extreme doses, but then diarrhea is a dangerous side-effect). $\endgroup$ – Nick T Apr 17 '17 at 22:34
  • $\begingroup$ Bupropion is not particularly addictive - at least not if unless you take it intravenously. $\endgroup$ – papirtiger Apr 17 '17 at 23:47
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    $\begingroup$ It could be as simple that it just makes them have a good time and be happy at the inn. $\endgroup$ – gloomy.penguin Apr 18 '17 at 0:51
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    $\begingroup$ Adding opium to food for nefarious purposes has really happened in china in a few documented cases in the last couple of years. $\endgroup$ – rackandboneman Apr 18 '17 at 15:44
  • $\begingroup$ theguardian.com/world/2016/jan/22/… $\endgroup$ – Rodrigo Menezes Apr 18 '17 at 19:43

No need to make it too complicated:

Refined sugar

If it is before 12th century, the only available sweetener was honey. And, while enjoyable, it certainly was not as sweet as pure sugar, and has a stroung flavour that may make it not suitable for anything.

So refined sugar and the products incorporating it would be a very incorporation to your girlfriends goods. Over the two proposals already made it has two main advantages:

  • Can be produced locally, from white beet, without the need of introducing new, suspicious plants.

  • Its effects are less noticeable (if your girlfriend patron's suddenly cannot sleep at night or become too nervous, maybe some researcher1 could come and ask some questions, using their famed methods).

UPDATE: In consideration of paptiger's comment, it is worth noting that the refining process might be more complicated than I originally thought and so the whole idea of producing refined sugar "locally" may be more complicated that I made it sound.

1Or, by their latin title, inquisitor.

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    $\begingroup$ Sugar does not cause addiction. You can create a want and a consumer need for it, yes. But addiction... no. $\endgroup$ – MichaelK Apr 17 '17 at 19:27
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    $\begingroup$ Proper Spanish Inquisitors were usually Baccalaureates in Law from some university (typically Salamanca) and weren't quite as free with the use of those "famous" methods as their English contemporaries would have you believe. In fact, some were downright bureaucratic. In any case, if the OP's girlfriend's patron suddenly cannot sleep at night, he can certainly claim that it's a stimulant and ask him to avoid taking it for two hours before going to sleep (or take it if he's going to bed but not sleeping, if you know what I mean). $\endgroup$ – Wtrmute Apr 17 '17 at 19:31
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    $\begingroup$ Producing refined sugar from beets is not easy - it took many generations of selective breeding to get a high enough sugar content and then you need the right chemicals to separate the sugar from the beet pulp. $\endgroup$ – papirtiger Apr 17 '17 at 23:59
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    $\begingroup$ @Wtrmute the "Spanish Inquisition" is not what I am talking about. What is refered to as "Spanish Inquisition" was a reintroduction of the old, medieval Inquisition, at the end of the XV century, and this question is about medieval times. $\endgroup$ – SJuan76 Apr 18 '17 at 8:34
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    $\begingroup$ @Wtrmute : this myth pops up on this site again and again, as most people learned about the inquisition only from Monty Python or rants in various online forums. In real life, unless you were organizing an armed rebellion or made someone very powerful very mad at you, you were pretty safe from the inquisition. They didn't torture you or burn you as a heretic just for some eccentric behavior. In fact, only around 2-3% of their suspects were executed (in a time period where you could be executed for stealing a pig), the vast majority was declared not guilty. $\endgroup$ – vsz Apr 19 '17 at 4:41

Another solution that would greatly increase demand - SPICES

Spices were highly valued in that time period (as some are still to this day), have even been used as currencies from time to time, and were a factor in creating trade routes and finding new (to Europeans) lands.

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    $\begingroup$ You know nothing. Good answer! $\endgroup$ – Mad Physicist Apr 18 '17 at 15:51
  • $\begingroup$ Which spices? Things like saffron and salt, or the kind that lets you see the future? $\endgroup$ – Fund Monica's Lawsuit Apr 19 '17 at 5:01

The most innocuous one would be nicotine, which already occurs in potatoes and Tomatoes as well as other vegetables at low levels. Small amounts added to the food would give them a boost, and would make the meals seem very satisfying. It wouldn't be as effective as adding a more powerful agent, nor would the withdrawal be debilitating.

If you can find a way to boost the fat and sugar content as well, you've got your food addition.

  • $\begingroup$ Maybe innocuous is not the right word here: en.wikipedia.org/wiki/Nicotine_poisoning: The estimated lower limit of a lethal dose of nicotine has been reported as between 500 and 1000 mg $\endgroup$ – SJuan76 Apr 17 '17 at 18:16
  • $\begingroup$ @SJuan76 caffeine also has a lethal dose, at 30,000mg $\endgroup$ – Richard U Apr 17 '17 at 18:31
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    $\begingroup$ I did not claim it did have no lethal dose, but certainly it is easier to accidentally overdose someone at 500 or 1000 mg than at 30 g. $\endgroup$ – SJuan76 Apr 17 '17 at 18:34
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    $\begingroup$ Also, recall that both potatoes and tomatoes are American (more properly Andean and Central American), and thus unknown in Mediaeval Europe. $\endgroup$ – Wtrmute Apr 17 '17 at 19:35
  • $\begingroup$ @Mindwin those are only two examples, it also occurs in Eggplants, peppers, teas, cauliflower and various nightshade plants. $\endgroup$ – Richard U Apr 17 '17 at 20:11

What about New World food ?

You don't need actual drugs: look around you, apart from sugar, we're all dying for potatoes. Their introduction in Europe drastically changed the food regime, to the point we have forgotten a lot of what the medieval Europeans used to eat.

Similarly, tomatoes or corn may do the job (think pop-corn !).

If you have to bring only small quantities, try spices like cinnamon, curry, or vanilla. Not addictive either, but their novelty surely would attract rich costumers.

  • $\begingroup$ I am baking up tater tots as I type this. You are so correct. Humans everywhere crave delicious spuds. $\endgroup$ – Willk Apr 17 '17 at 22:35
  • $\begingroup$ It actually took quite a bit of convincing to get commoners in Europe to eat potatoes. And much of the reason growing potatoes became commonplace was because the are easy to grow and give a very big yield - not the flavour. $\endgroup$ – papirtiger Apr 17 '17 at 23:52
  • $\begingroup$ One bad side is new food is unusual and therefore could not like. Another that you have to bring dozens kilogrammes of this food every day - just for dozen of lodgers. And what you will do when popularity raising and 50-100 guests come to eat your delicious? $\endgroup$ – ADS Apr 18 '17 at 6:46
  • $\begingroup$ @ADS. Plant the seeds. Literally. $\endgroup$ – Mad Physicist Apr 18 '17 at 15:53
  • $\begingroup$ Tomatoes were also considered to be toxic. I'm still not entirely convinced that they're not :P $\endgroup$ – Monty Wild Apr 19 '17 at 0:42

Add Caffeine where its bitterness is either welcome or can be masked well enough with more sugar. Coffee was known in Europe by the early 17th century. See http://www.ncausa.org/About-Coffee/History-of-Coffee.
Hey, if it works for the cola industry, I think it'll work for you. ;-)

(This presumes sugar or honey is available to do the sweetening.)

This strategy is taken to the limit (and maybe beyond) with some mystery addictive substance in the classic SF/social-satire novel, The Space Merchants by Pohl and Kornbluth, see: https://en.wikipedia.org/wiki/The_Space_Merchants


I think MSG(mono sodium glutamate) is the best contendor. Its an additive and generally considered harmless. So no one will even notice it.

Though its tasteless but almost all MNC firms add this in their products to give extra burst of flavor. Medieval people will fall in love with your girl's dishes. And the girl with you :P.

  • $\begingroup$ All dishes will become more tasty thanks to the umami :) $\endgroup$ – Onoper Jun 25 '18 at 12:37

Something else to consider is that the economics of a medieval society were a bit different to what they are now and there may be a limit to the potential for local trade simply because people don't have the disposable income to eat out, even if they really wanted to.

A better approach might be to try to encourage more passing trade. Travellers are obviously much less able to cater for themselves.

Fortunately the period has a ready made answer to this in the shape of pilgrimage which was was big business and religious sites went to great lengths to acquire the most prestigious relics to attract visitors. Sites with a particularly attractive religious draw could make serious money with potential knock on benefits for local entrepreneurs.

So a logical plan is to arrange for a suitably impressive miracle to pull in the punters, if this results in saleable products then so much the better, something like a healing spring would be ideal.

You need to be a bit careful that the miracle ticks the right theological boxes as being labelled a sorcerer could backfire pretty badly but as the church is also set to benefit they are unlikely to scrutinise any 'miracles' too closely and similarly you will be only benefiting indirectly. Just let the church do the marketing for you and wait for the hungry pilgrims to flock in.

An additional benefit is that you only need a few convincing 'miracles' to get the ball rolling after that it should be pretty much self perpetuating.

  • $\begingroup$ Finally, an answer that addresses the fact that the business model described in the question is unrealistic on its own. All the MSG in the world won't help when literally no one in the area can afford your food. $\endgroup$ – Mad Physicist Apr 18 '17 at 15:58
  • $\begingroup$ Very good points, but you missed that the 'miracles' involved could be piously tending the plants OP was asking about. Then their addictive effects have a 'holy' pedigree that checks those boxes as well. $\endgroup$ – lly Apr 19 '17 at 12:07

As already mentioned, anything dramatic enough to act overnight—MDMA, e.g.—is definitely going to bring charges of sorcery, witchcraft, &c. Anything longer term that actually works—nicotine, caffeine, &c.—is going to risk the same thing at a slower rate. Addiction means the customers will notice ill effects when they avoid or are forced to be apart from the place, and someone is going to tell the priest.

The way to avoid that static is to take your time and coöpt the authorities. Anything that involves processing hazardous chemicals—hey, Mr. White—is a nonstarter but anything natural that can grow in their climate is fair game for months of worshipful prayers, devotion, and care. Then when it turns out there is a miraculous power in the food prepared from those ingredients, it's thanks to the divine intercession of Our Mother of Marlboro, the Blessed Virgin of the Iron Buddha, or St Coffa of Abyssinia.

You're missing the trick, though. Addicting the peasants and coöpting the priests is the chump move.

Coöpt the guys with the swords.

Take a modern weightlifter's guide back with you and a hefty supply of protein, creatine, &c. Work in the prayers and whatnot, but the main idea is to get the local knights and soldiers bulked and on your side. Maybe have a big bad the next village over whose ass they can kick after a few weeks on your diet-&-exercise routine. Your gf and her family will have a title and estate by Michaelmas.

At that point, you could work in steroids and anything heavier: they're already on your side and can "vouch" for you against any interfering priests. You still might not want to, though: all the deleterious side effects could turn them against you and her.

  • $\begingroup$ See @ChrisJohns comment for more benefits to going the miracle route. $\endgroup$ – lly Apr 19 '17 at 12:06

I think your character would do well with some sugar and a show. The sugar is just the most convenient placebo available. Then your character or his girlfriend needs to sell it (I mean lie convincingly) about its amazing properties. Call it what you will. Medieval herbals such as this Anglo-saxon one tended to have a mix of local lore and Mediterranean plants mentioned in the manuscripts they were copying from. Your locals aren't automatically going to think "demonic" when encountering something new. Exotic works. http://blogs.bl.uk/digitisedmanuscripts/anglo-saxon/


Deep Fryers

I would certainly say that our culture is enamored with things that are deep fried (bonus points for it also being on a stick)

It should work for just about anything that is already available to be cooked, think vegetable tempura and you're on the right track. The only trick might be sourcing the breading and oil necessary for cooking in that way.

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    $\begingroup$ Deep fried foods were already a thing in the Middle Ages. There is even a recipes for funnel cake complete with a description of the funnel. $\endgroup$ – Mazel Apr 18 '17 at 14:48
  • $\begingroup$ @Mazel. While the equipment for deep frying things would be readily available, it is likely that the ingredients would not be. That is where the boyfriend could help out a bit. $\endgroup$ – Mad Physicist Apr 18 '17 at 16:00
  • $\begingroup$ a method of refrigeration would also be a good idea $\endgroup$ – gloomy.penguin Apr 24 '17 at 16:22

Thousands of years ago the Chinese faced this very problem. One of their most recent answers to this problem is Monosodium Glutamate, otherwise known as MSG. Just make your normal tasteless food, then sprinkle some on. MMMMMMM (as Homer Simpson would say).

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    $\begingroup$ MSG does not cause addiction. It will not improve the existing food, either — it would let them make similarly savory food cheaper, using less meat or less time to make stock. What's the reference to “thousands of years”? $\endgroup$ – JDługosz Apr 18 '17 at 4:25
  • $\begingroup$ Some information on the extraction of MSG. - chemistry.stackexchange.com/questions/64266/… $\endgroup$ – KalleMP Apr 18 '17 at 16:46

In theory, you don't even need newer substances or technologies for this: There is this "explanation" to why humans used to see monsters, dragons and other fantastic creatures in the past, and that is mostly connected to a very common dietary item: wheat.

Consider the existence of a fungus that attacks the wheat crops. It does not destroy them, neither makes them inedible: it just slightly changes the appearance (no changes to taste or durability).

The point here is that this fungus (called Ergot), as it develops in the wheat, produces some chemical substances called alkaloid ergotamine, a complex molecule consisting of a tripeptide-derived cyclol-lactam ring connected via amide linkage to a lysergic acid (ergoline) moiety, and other alkaloids of the ergoline group that are biosynthesized by the fungus. Ergot alkaloids have a wide range of biological activities including effects on circulation and neurotransmission. (1 - Direct quote from Wikipedia, please see link below).

Now imagine, you live in a society where a large part of the diet is based on wheat or rye, and those products are contaminated by this fungus. You eat some bread, see a large bird, but interpret that as a dragon, or see a a man riding a horse and visualize a centaur (of course this is just a very simplistic interpretation of meta-mythology); most people would be paying to see that magic.

So, you have access to the fungus, and you can now produce products that have considerable quantities of it, quoting them as having "magical properties". More than the lysergic properties of your bread, there are also other small advantages, such as refined carbs that could easily create addiction (as stated in other answers).

In this case, you can even save some fuel of your time machine by using the spores found in the wheat around the place you are, if those are available (and considering how widespread this fungus was on past times, it probably is).

Obs: The only slight problem of this situation, and of using any kind of substances to generate addiction, is that you are in the middle ages, so there would be high chances that the women you are trying to help would be branded as witches. Then you´d have a much bigger problem in your hands (good luck with that one).

Source 1: https://en.wikipedia.org/wiki/Ergot

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    $\begingroup$ You'd need to do some refining on the Ergot, however, as it seems to have some pretty bad side effects. $\endgroup$ – Marshall Tigerus Apr 18 '17 at 17:50

opium (codeine and morphine), cocaine (affects the dopamine levels), cannabis (Tetrahydrocannabinol) - those were all legal and unregulated back then... if you don't mind the moral repercussions.

You could perhaps just have pot burning like incense in the tavern - they'll feel great, get the munchies, and come back for more.

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    $\begingroup$ Welcome to Worldbuilding. Do take the tour and check out the help centre when you have a moment. A thought on your answer: While these drugs may (or may not) cause customers to come back for more, the answer is a bit short and could be improved by some more information. How did you intend to use the drugs, to sneak it in to the food? What effect would you consider be the best for the purpose of the question? That they get dazed and lazy (opium) or that they get hungry and introspective (THC)? $\endgroup$ – Mrkvička Apr 18 '17 at 18:47

spike it with addictive drugs derived from herbs. or you can just use cocaine. Or Opium. If you want to get technical you can use peer pressure too, but that's complicated and really skirts the line of "addiction".

Now that I see you're coming from the present though, you can just use other opioids. I'd crush up some pills and rub it in the meat. Customers feel really good when they eat her food, but feel really really really bad when they don't. As an added bonus they constantly need more. Tobacco would be another good one. Get some concentrated tobacco and put it in the syrup or jelly or jam. Suddenly they're super pissy without it. I think you should be able to get some of that legally in a vape kit, but I don't vape so I don't know.

Honestly tobacco is your best bet here.


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