English meadows and forests are and were full of psychoactive substances.
They were used.
Partially isolated, on their own. But also in what psychiatrists call polytoxicomania. In what aficionados call synergistic combinations.
This answer defines 'drugs' as mind-altering substances. The psychoactives do not need to be on the level of effectiveness of Oktoberfest inebriation or Leary-like tuning out. An altered state of mind is all that is needed, as that scale doesn't start at injected fentanyl-speedball while smoking crack. Such all-out – between entheogenic or even destructive – experiences are all possible with the listed substances, but they work also in smaller doses.
Beer contained for example Rhododendron tomentosum or Hyoscyamus, Belladonna or Mandrake. And most abundantly it was drunk in the form of gruit:
Gruit was and is a combination of herbs, commonly including sweet gale (Myrica gale), mugwort (Artemisia vulgaris), yarrow (Achillea millefolium), ground ivy (Glechoma hederacea), horehound (Marrubium vulgare), and Calluna heather (Calluna vulgaris). Gruit varied somewhat, each gruit producer including different herbs to produce unique flavors and effects. Other adjunct herbs include juniper berries, ginger, caraway seed, aniseed, nutmeg, cinnamon, mint…
If it contained the classic rhododendron, it had mainly ledol, if it had bog myrtle it offered a lot of pleasant essential oils. Those were until recently described as "extremely poisonous", "causing headaches and nausea". But recently it was described as anticancer, antioxidant, antimicrobial etc (eg M. Nakata, T. Myoda, Y. Wakita et al.: Volatile components of essential oil from cultivated Myrica gale var. tomentosa and its antioxidant and antimicrobial activities. In: Journal of Oleo Science. 62, 9, 2013.)
And alcohol is not the only psychoactive ingredient today, as you might as well throw in some hemp, (a drug in use long there before any European would know that this part of Asia would be called 'Europe') — or like it was done in Bohemia and Bavaria: hops!
Unlike modern beers that are flavored with flowers of the hop plant, the Eberdingen-Hochdorf brew probably contained spices such as mugwort, carrot seeds or henbane, in Stika’s opinion. Beer makers are known to have used these additives by medieval times. Excavations at the Celtic site have yielded a few seeds of henbane, a plant that also makes beer more intoxicating.
In that sense the purity 'law' for beer from Bavaria can be seen as a double sided sword. Most gruit components improve taste and effect, being more on the stimulating side, while hops has a profound downer effect. One call it the first consumer protection law for quality control, others see an early form of prohibition at work: alcohol and stimulant combination can more easily fuel rebellion and outrage, while sleepy hops beer consumers make very good subjects.
More inspiration on that found in "Of Hony. A collection of Mediaeval brewing recipes for mead, metheglin, braggot, hippocras &c. — including how to process honey — from the 1600’s and earlier." by Mistress Elska á Fjárfelli (Susan Verberg, 6/2018.) Example recipes:
4 Strong claret for the house [?].
Take of cinnamon 1 lb. as it comes out of the bale; of ginger, 12 ounce in the same manner; 3 quarter of a pound of pepper; 2 ounce of long pepper; 2 ounce and a half of grains of paradise; 3 ounce and a half of cloves; 2 ounce and a half of galingale; 2 ounce of caraway; 2 ounce of mace; 2 ounce of nutmeg; 2 ounce of coriander; a quarter of a pint of aqua arduant; with 3 gallons of honey: recipe for 20 gallons of claret.
5 potus ypocras.
Take a half lb. of canel tried; of gyngyuer tried, a half lb.; of greynes, iii unce; of longe peper, iii unce; of clowis, ii unce; of notemugges, ii unce & a half; of carewey, ii unce; of spikenard, a half unce; of galyngale, ii unce; of sugir, ii lb. Si deficiat sugir, take a potel of hony.
5 Strong hippocras.
Take half a pound of cinnamon tested; of ginger tested, a half pound; of grains of paradise, 3 ounce; of long pepper, 3 ounce; of cloves, 2 ounce; of nutmeg, 2 ounce and a half; of caraway, 2 ounce; of spikenard, a half ounce; of galingale, 2 ounce; of sugar, 2 lb. If deficient in sugar, take a potel of honey.
Especially for medieval mead, the intense bitter wormwood Artemisia absinthium and its thujone make for an actually pleasant tasting drink.
To name a few candidates more, from recent folk tradition, albeit in Romania:
Folklore sources have a rich representation of the use of native flora or imported vegetal products for various purposes, hence the classification of herbs as “medicinal”, “mythological”, “inspirational”, “magic”, etc.
The mandrake has a central role in therapeutic and psychotropic representations, and has been regarded as an epitome of miraculous plants, with numerous mystical and magic powers. It has been known and used as an aphrodisiac and for the dilation of the pupils (large and bright eyes, a standard of beauty in the medieval times, hence the name of belladona), anaesthetic, antidepressant, but also knowing the toxic potential of an overdose – a state of ecstatic frenzy (see the maenads – priestesses of Bacchus), and erotic hallucinations (due to the parasympathomimetic substances: hyoscyamine, atropine, scopolamine). In the folk Romanian medicine, we also found other potentially psychoactive plants: bay laurel, jimson weed or devil’s trumpet (Datura stramonium), valerian (Valeriana officinalis), corn poppy, aconite or monkshood (Aconitum tauricum), the Herb of Grace (Gratiola officinalis), ergot (Claviceps purpurea), henbane (Hyoscyamus niger), motherwort (Leonurus cardiaca), white bryony (Bryonia alba), cowbane (Cicuta virosa), harmal (Peganum harmala) (contains the alkaloid harmaline, a MAOI, similar with telepathine from Ayahuasca), known as early as the Getae-Dacian’s times 1. Confusingly, but based on a clinical similitude, most of these plants were described under the generic name of mandrake, a ritual and healing archetype of the ethnobotanical research.
— Gabriel Gorun & George Cristian Curcă & Sorin Hostiuc & Octavian Buda: "“Legal highs” in Romania: historical and present facts", Rom J Leg Med 19 73–76  DOI: 10.4323/rjlm.2011.73 (PDF)
All these weeds and herbs and leaves and roots and seeds and barks and mushrooms were pressed into pills, most famously in 'oriental happy pills'. Functionally these are equivalent to ma'jun or electuary.
These were also applied as suppositories or topically in so called flying ointments, delivering the good stuff transdermally. Since these work best on thin parts of skin or even mucous membranes, that method gave rise to what the perversely minded religious people imagined as witches rubbing that onto a broom, to… well, ride on it into the sky.
Stuff like hemp or frankincense was also burned in numerous combinations. Catholic mass really gets you into different mood than a Protestant meeting that merely tells you to work harder. In fact all ancient religions are closely linked to psychoactive drug use, as evidenced by written accounts and archaeological record.
The entire Christmas business is another such occasion when copious amounts of cinnamon, nutmeg, saffron, pepper etc were consumed in amounts that even after long caravan travel wouldn't have lost that much of their pungency, but retained some of their mood lifting or even hallucinogenic aspects. Cookies get you a bit high, and not solely from sugar.
A note on these exotic spices and their alleged price: saffron is the most expensive of them all. It tastes quite lousy and makes the dough or rice a bit of a nice yellow colour. If it weren't for the psychoactive effects nobody would bother to pick up these tiny stamps from small flowers. Children are of small enough weight to get 'situations' with it, but it works on adults as well. That said, nutmeg is unique for its nice concentration of psychoactive oils. But they are also found in for example parsley.
As we now think often of 'drugs' as isolated substances having a profound effect, this is neither helpful for describing pre-modern drug use, nor the effects of combined consumption. How much nutmeg anyone consumes is less relevant than how much eugenol is within a persons system and how effectively is it transformed in the liver, how long can it act on neuronal target sites, before it's metabolised. All of these steps can be influenced by co-administration of other foods, drinks and drugs. From balancing out side effects to dramatically increasing them, the range of possibilities is huge.
The works of ethnopharmacologists summarise these practises, even if they rarely focus on middle age Europe.
One prolific author team that does would be Christian Rätsch and Claudia Müller-Ebeling:
— "Räucherstoffe: Der Atem der Drachen. 72 Pflanzenporträts. Ethnobotanik, Rituale und praktische Anwendungen", AT: Aarau, 62012.
— "Enzyklopädie der psychoaktiven Pflanzen: Botanik, Ethnopharmakologie und Anwendung", AT: Aarau 132016.
— "Bier: Jenseits von Hopfen und Malz. Von den Zaubertränken der Götter zu den psychedelischen Bieren der Zukunft", Orbis: München, 2002. (A list based on that book is online)
– "Lexikon der Liebesmittel: Pflanzliche, mineralische, tierische und synthetische Aphrodisiaka", AT: Aarau, 2003.
— "Der heilige Hain: Germanische Zauberpflanzen, heilige Bäume und schamanische Rituale", AT: Baden, 2005.
— "Walpurgisnacht: von fliegenden Hexen und ekstatischen Tänzen", AT: Baden 2007.
— "Abgründige Weihnachten. Die wahre Geschichte eines ganz und gar unheiligen Festes", Riemann: München, 2014.
–– "Die 'Orientalischen Fröhlichkeitspillen' und verwandte psychoaktive Aphrodisiaka", VWB: Berlin, 1990.
When we think 'drugs' we might think of exotic plants, and even exclude alcohol. But just like traditional Chinese medicine, the old European pharmacopeia includes stones, metals, and animal products. And not all of them are hokum. While some unfounded legend might surround European bufo toads' secretions usage of for example metallic arsenic in the form of hidrach widely gathered in Europe since ancient times is documented for medical and recreational use in Europe until the 1930s.
One very notable historic reference supports the first ethnographic evidence of an early "smoking culture" in temperate Eurasia (Sherratt 1995). This indication concerning Cannabis comes from Herodotus (c. 446 B.C.), in which he describes the post-funeral purification ritual of Scythians on the Pontic steppes: "On a framework of three sticks meeting at the top, they stretch pieces of woolen cloth, taking care to get the joins as perfect as they can, and inside this little tent they put a dish with red-hot stones on it. Then they take some hemp seed, creep into the tent, and throw the seeds on the hot stones.
— M. D. Merlin: "Archaeological Evidence for the Tradition of Psychoactive Plant Use in the Old World ", Economic Botany, Vol. 57, No. 3 (Autumn, 2003), pp. 295–323
This was different in the past: during the Middle Ages and the Renaissance the unique sensorial qualities of saffron were employed socially to encode the dried stemma of the crocus sativus L. as an object of conspicuous consumption reserved for the wealthy. Newly discovered sources demonstrate that the perception of saffron was a complex phenomenon that builds on the sensorials but surpasses them: as a tonic, mood elevator, antidepressant, and hallucinogenic drug saffron could be used to achieve various altered perceptions ranging from heightened sensitivity to states of trance.
— Volker Schier: "Probing the Mystery of the Use of Saffron in Medieval Nunneries", The Senses and Society, 5:1, 57–72, 2010.
Quite notable in this regard is the pharmacological oeuvre of Hildegard von Bingen, a nun. She described substances and recipes as well as their (mind altering) qualities in quite some detail. Nutmeg lifts the mood in certain doses, makes you funny in higher ones, and quite stupid in the long run…
To modern readers, some of these descriptions in her work might read a bit strange, as they are based on and described according to humoral theory. But her hands-on experience with many substances is evident nonetheless. She is not only known for being a mystic and building her knowledge on ancient Greek and Latin authors, but also a documented sufferer of migraines – and consequently self-medication.
Nutmeg [nux muscata] has great warmth and good temperament in its strength. If a person eats nutmeg, it opens the heart and purifies the senses and brings a good disposition. Take some nutmeg, an equal weight of cinnamon, and a little cloves. Grind these to a power, add a similar amount of whole wheat flour and a little water, and make a paste from this. Then eat it often. It will calm all the bitterness of heart and mind, open the heart and clouded senses, and make the mind joyful. It will purify the senses and diminish all the noxious humors; it will contribute good liquid to the blood and make one strong.
Belladonna [dolo] has coldness in it. It holds weariness and sluggishness in its coldness. In the earth and place where it grows, diabolic influence has some part and union in its craft. It is harmful for a person to eat or drink it because it agitates the spirit, just as if the person were dead. Nevertheless, if the skin and flesh are perforated with great and piercing ulcers, let the person take a little goose fat and as much deer and goat tallow as he or she can get. Add a little bit—just as a single drop from a pen—of belladonna juice. Mix all this together and make an ointment.
— Bruce W. Hozeski (transl): "Hildegard’s Healing Plants – from her medieval classic Physica", Beacon Press: Boston, 2001.
The nutmeg mix is now part of a classic recipe for cookies, albeit in much lower dose then what went around in monasteries at the time…
Note though, that the tried and proven psychedelic effects of all of these ingredients might actually be more like micro-dosing in many cases, as we seldom have exact measurements for the actual amounts used. And for some of these, the 'therapeutic window' is small. Not everything is as harmless as cannabis. (Hildegard's take on it)
For one, there might have been quite a few high-class psychedelic mushroom poisonings, suffered by people trying out something new they found in the woods. On the other hand eating false wheat or if in wet summers rye get infested with Claviceps purpurea a lot of people will have experienced ergot poisoning. In other words, suffered from an LSD experience they didn't want, with added cramps and other physical discomfort and worse. Europeans apparently kept the knowledge to use this medically, for example to induce abortions, but seemingly lost the ability to separate the hallucinogens from the pure poison, a feat the Greeks once mastered for rituals.
In one Late Old English magico-medical text written at sometime in the late tenth or early eleventh century AD the following recipe is found: ‘A sleep-drink: radish, hemlock, wormwood, henbane; pound all the plants; place in ale; let stand one night; give it to be drunk.’ This evidence, though very late, tends to show that rather than using henbane for its potential psychedelic effects, as some have suggested in the case of the Scottish find, it was used in beer as part of traditional medical lore; however, without providing proper quantities such a recipe could easily turn into a fatal drink rather than a simple sleep potion.
— Max Nelson: "The Barbarian's Beverage: A History of Beer in Ancient Europe", Routledge: London, New York, 2005. (PDF)
A most interesting aspect of old plants is that some of them we think we know – and find harmless. But they may be not:
A typical one, dated 800 AD, from the Benedictine monastery at Monte Cassino in southern Italy, used a mixture of opium, henbane, mulberry juice, lettuce, hemlock, mandragora, and ivy.
There is no evidence to suggest that similar recipes existed in the British Isles at that time. However, in 1992, an extensive study succeeded in identifying a large number of similar recipes in late medieval (12th–15th century) English manuscripts. All identified the anaesthetic, a drink, by the name dwale. A typical manuscript (fig 1), translated into modern English, reads:
“How to make a drink that men call dwale to make a man sleep whilst men cut him: take three spoonfuls of the gall [bile] of a barrow swine [boar] for a man, and for a woman of a gilt [sow], three spoonfuls of hemlock juice, three spoonfuls of wild neep [bryony], three spoonfuls of lettuce, three spoonfuls of pape [opium], three spoonfuls of henbane, and three spoonfuls of eysyl [vinegar], and mix them all together and boil them a little and put them in a glass vessel well stopped and put thereof three spoonfuls into a potel of good wine and mix it well together.
In addition to alcohol, the ingredients in dwale are, in order of their listing, bile, hemlock, bryony, lettuce, opium, henbane, and vinegar.
— Anthony J Carter: "Dwale: an anaesthetic from old England", BMJ 1999;319:1623–6
That lettuce part reads quite intriguing? Healthy leafy greens – for anaesthetics? Even ordinary modern lettuce is known to contain substances that makes males impotent and kills sexual desire in both sexes. But in this case, it is even worse – or better? – than that. The wild form of lettuce is a whole different beast than the lust killer on modern sandwiches. Lactuca virosa was grown, harvested, processed and used just like opium. Only slowly loosing ground when real opium – imported, as unstable weather in Northern Europe isn't ideal for stable and predictable alkaloid content – became cheaply accessible.
— John M. Riddle: "The Introduction and Use of Eastern Drugs in the Early Middle Ages", Sudhoffs Archiv für Geschichte der Medizin und der Naturwissenschaften, Bd. 49, H. 2 (JUNI 1965), pp. 185–198.
— Bruce P. Flood, Jr.: "Sources and Problems in the History of Drug Commerce in Late Medieval Europe", Pharmacy in History, Vol. 17, No. 3 (1975), pp. 101-105.
— Bruce T. Moran: "The 'Herbarius' of Paracelsus", Pharmacy in History, Vol. 35, No. 3 (1993), pp. 99–127.
— Michael McVaugh: "The "Experience-Based Medicine" of the Thirteenth Century", Early Science and Medicine, Vol. 14, No. 1/3, Evidence and Interpretation: Studies on Early Science and Medicine in Honor of John E. Murdoch (2009), pp. 105–130.
Evidence for the diffusion of Cannabis in Europe and the Middle East
The most comprehensive English language survey of the archeological evidence for Cannabis early history in Europe is by Godwin (1967b). Dörfler (1990) provides a more recent German language overview of both macro-fossil and pollen evidence for the early distribution and diffusion of Cannabis in Europe.
Bartley et al. (1976) shows Cannabis pollen from the Durham lowlands that comprise 19% of the total pollen count in a continuous curve from 1730 to 852 BP. Birks (1965) shows a Cannabis occurrence from Cheshire Moss dating to ca. 1350 BP. Peglar (1993) studied the vegetational history around Diss Mere on the eastern English coast and revealed an almost continuous Cannabis pollen curve for the area from ca. 1100-150 BP. Using a pollen percentage diagram, she showed the almost mirror-like occurrence of hemp with cultivated rye, flax, barley, and mustard (Brassica) as well as the near omnipresence of plantain and nettle (Urtica). Historical records show the area was the center of the hemp industry in England. Pursehouse (1961) noted that 15% of all sown areas in the Waveney valley supported hemp, and her study correlates with this information nicely. Her diagram showed a very rich pollen assemblage, and there are good records of the flora and climatic conditions around the area, but her study had some potential weaknesses. First, the sediments she studied were calcareous, which can skew carbon-14 dating (Peglar 1993), making pollen-influx diagrams and rates of palynological change impossible to accurately document. Secondly, she admitted that sedimentation rates for the area may also show marked changes, and local disturbances are likely to have re-deposited pollen grains in the study site.
— Michael P. Fleming & Robert C. Clarke: "Physical evidence for the antiquity of Cannabis sativa L."
Anglo-Saxons brought their hemp culture with them to England. Definitively written evidence for psychoactivity comes from around 1200, but overall Europeans who wrote were drunks, primarily:
Nonetheless, until the 20th century there is a paucity of European written references to cannabis’s psychoactive properties, perhaps due to the popularity of beer and wine (Mikuriya 1969).
— Barney Warf: "High Points: An Historical Geography Of Cannabis", Geographical Review 104 (4): 414–438, October 2014.
In summary we can conclude that it is indeed very likely that almost everybody tried and then used almost everything that agreed with him/her. On the scholarly level we find written records detailing a large portion of known inebriation substances, so the theoretical and scientific framework would have been available. From archaeological finds we see indicators of seeds, pollen, tars and other residues that also indicate widespread knowledge and use of old, traditional and newly introduced drugs. What we lack is a continuous tradition that would reliably show the oral wisdom of folk medicine or drug culture. Equally problematic is the lack of concrete measurements in recipes and sometimes difficult to trace 'active ingredients' as correct and unambiguous identification was and is sometimes difficult. It is for example unclear why the bog bilberry Vaccinium uliginosum is commonly called the 'inebriating' or 'drunken berry' in Germany, as neither inebriation after consumption nor druglike substances in it could be found (the accusation of 'folk etymology corrupting translation from Latin ruscus is not convincing on the one hand and even if true opens up a multitude of mixups in identifications).
For the whole of 'England' and the entirety of 'high middle ages' it is also not very likely to paint a really detailed and complete picture. While we might infer a lot from what was there, what was known what was available, we cannot infer with certainty whether everyone was more or less intoxicated all the time. Local fashions might have differed quite a lot: one village in effect preferring beer with henbane alkaloids, another one next to it liking more the datura belladonna mix as 'our thing'.