My sister is a witch. Or, more precisely, a Wiccan astrologer and tarot reader. Growing up as a kid who worshipped Carl Sagan and Stephen Hawking, I found it hard to square her worldview with my own. But that didn’t stop me from feeling a thrill when I visited her shabbily ornate, mist-clad Victorian house in San Francisco’s Mission District in the late 1990s. The city outside hummed with the techno-utopian dreams of the dotcom bubble, but inside candles burned, tarot cards shuffled, and books of occult lore beckoned from attic corners. It was in those candlelit rooms that I began to understand the appeal of the non-rational, and it changed my life.

When I began my graduate studies in history, I decided to focus on the period when magic and alchemy morphed into modern science. I was especially fascinated by John Dee, the wizardly court astrologer to Queen Elizabeth I. Although Dee believed he could speak to angels, he was also one of the leading mathematicians and geographers of his era. Robert Boyle and Isaac Newton followed in Dee’s footsteps, conducting empirical investigations of nature alongside studies of Biblical prophecy and alchemical secrets. John Maynard Keynes had it right when he observed in 1946 that Newton was not the first scientist – he was the last of the magicians. Newton’s generation especially loved to search for ‘occult virtues’ – hidden phenomena latent in nature – and they found them in psychoactive drugs, along with a mystery that is still with us today.

I found my first hint of this Enlightenment obsession in the journals of Newton’s great rival, the quarrelsome but brilliant polymath Robert Hooke. On a fall day in 1689, Hooke ducked into a London coffee shop to buy a sample of cannabis from an East India Company merchant who’d become an aficionado of the plant. Hooke tested the drug’s effects on an anonymous subject and reported that it left the patient ‘unable to speak a Word of Sense’. Despite this, the verdict was good: the consumer was ‘not giddy, or drunk’ and seemed ‘very merry’, laughing, dancing and performing ‘many odd Tricks’. Hooke reported to his fellow members of the Royal Society that cannabis was a valuable sleep aid, and could even ‘be of considerable Use for Lunaticks’. He predicted that London merchants might make a fortune selling it.

In other words, the same novel sensory effects that made substances such as tobacco, opium and cannabis desirable to global consumers also made them fascinating for the earliest experimental scientists. But what did those drugs mean – for them, and for us? How did our modern binary between ‘illicit drug’ and ‘valuable medicine’ come into being?

Drugs have had a bad reputation since at least the time of Shakespeare, whose sleazy, potion-dispensing apothecary in Romeo and Juliet enables that play’s tragic finale. Shakespeare tended to associate drugs with things such as witches (‘mixture rank, of midnight weeds collected’) or Catholic assassins (‘drug-damn’d Italy’). But in the 17th century, drugs acquired associations with the non-European world: the fever-ridden islands of the Caribbean, tropical Africa, or the exoticised ‘East Indies’.

Even the humble coffee bean (from Yemen and Ethiopia) and tea leaf (from China) were regarded as exotic medicines in this period. Dr Cornelis Bontekoe, a physician in the employ of the Dutch East India Company, recommended in his Tractaat (1679) that up to two hundred cups of tea a day were ideal for good health. Another doctor wrote of the Chinese that tea ‘frees them from all those evils that the immoderate use of wine doth breed in us’. But for Christian Europe, the medicinal virtues of foreign drugs such as coffee, tea, opium and cinchona (source of quinine) were counterbalanced by their origins in the lands of heathens.

The King of England himself joined a public chorus of voices attacking ‘Indies drugs’ as unhealthy and un-Christian. King James’s A Counterblaste to Tobacco (1604) was a fantastically vitriolic diatribe against the ‘filthie custom’ of smoking, blaming it for ‘infecting the air’ at dinner tables throughout the realm – not to mention forcing smokers’ spouses into a ‘perpetual stinking torment’. James regarded smoking as a demonic custom from the shamanic cultures of the New World, evoking the ‘horrible Stigian smoke of the pit that is bottomelesse’. In other words: cigarettes smell like hell.

James wasn’t alone in demonising drugs. Inquisitors in Mexico City portrayed indigenous users of peyote as sorcerers, and Jesuit priests deep in the Amazon jungle sent back anxious reports about a plant called ayahuasca that allowed shamans to gather knowledge from evil spirits. Even the humble coffee bean provoked outraged diatribes about a ‘foreign liquor’ that had ‘bewitched’ consumers, causing enfeeblement, impotence, and worse.

Psychoactive drugs thus stood at the centre of debates about imperialism, religion, and globalisation, as well as science. They still do. It’s not a coincidence that drug cartels are among the most successful multinational enterprises of the 21st century – or that a global crusade against drugs, both prescription and illicit, is one of the core tenets of our era’s most successful new religion, the Church of Scientology.

It would not be a stretch to say that the wave of stimulants, intoxicants and narcotics that followed in the wake of Christopher Columbus helped to create modernity as we know it. From coffee, tea and chocolate to Adderall, painkillers and cocaine, and alternative remedies such as homeopathy and ginseng, consuming drugs stands at the centre of what it is to be a modern consumer.

The founding generation of scientists were, to put it mildly, not afraid of a little self-experimentation. Most infamously, a youthful Newton thrust a knitting needle behind his eyeball one afternoon, curious about how it would affect his vision (‘there appeared severall white, darke & coloured circles’). In the 1680s, Newton’s friend John Evelyn rubbed his face with a newly discovered luminescent chemical, phosphorus, that made him glow like ‘the face of the Moone’, seemingly unconcerned about its potential toxicity.

Scientists and historians today are far more cautious, and we should be thankful this is the case – the world needs more Marie Curies, and we don’t want them to die from their own experiments. But if we as a society have deemed the once-pernicious coffee bean to be harmless, perhaps we can safely resurrect some of coffee’s neglected peers. Why not practise a form of experimental history and approach forgotten drugs in the manner of an Enlightenment scientist?

Last summer, I met John Pollack, the curator of rare books at the Van Pelt-Dietrich Library at the University of Pennsylvania. I was there to see cookbooks – exceptionally old ones. Pollack explained to me that 17th-century cookbooks ranged far more widely than their modern descendants, cataloguing recipes for perfumes, pomades, cosmetics, dyes and drugs, in addition to delicacies such as ‘Lobster-Loaves’ and ‘Rabbitt fricasie’.

The cookbooks at Penn were a treasure trove. I found everything from ‘a Cake my Lady Oxford’s way’ that involved mixing cream with strong Spanish wine, to a salmon recipe featuring ‘water and salt and stale beer’. Most surprising, I found that recipes for medicinal drugs and foods were intermingled: a recipe for chicken pot pie circa 1700 appeared alongside ‘Snaill water, for a consumption’ that called for (you guessed it) a large amount of crushed snails, mixed with oddities such as ivory shavings and ‘red cows milk’, to be drunk every morning until the consumption, ie tuberculosis, subsided.

Early modern drug merchants ventured into Amazonia to carry back samples of the precious cinchona bark. Now you can buy it on Amazon for $8

I decided to emulate Hooke and Newton and try to recreate and sample two of the recipes I found in the historical archives, to see if they actually had psychoactive properties. The first experiment was the easiest. I would buy cinchona, the Amazonian botanical that is used to treat malaria, and try to make what was perhaps the most controversial new drug of the 17th century: cinchona extract, or ‘Jesuit’s powder’. Early modern drug merchants ventured deep into Amazonia to carry back tiny samples of the precious cinchona bark. Now you can buy it on Amazon for $8.

Cinchona is actually more familiar than it sounds: in addition to being the natural source of quinine, it’s also the key ingredient in tonic water. Artisanal cocktail fans have recently generated new demand for the bark in their efforts to outdo Schweppes. But no one, to my knowledge, has been brewing up the 17th-century version of cinchona extract. I set to work, drawing upon a recipe in the Portuguese apothecary João Curvo Semedo’s Polyanthea Medicinal (1697) and infusing the bark in boiling water along with an array of East Indian spices.

The verdict: cinchona bark tea is the bitterest thing I’ve ever encountered – so acrid that it acquires an entirely different sensation on the tongue, a transcendent state of bitterness evoking flavours of turpentine, bile, and crude petroleum. But does it actually have a physiological effect? Yes and no. I don’t have malaria, so I couldn’t test cinchona’s legendary efficacy as a fever cure. But cinchona’s active ingredient, quinine, is also known for provoking uniquely vivid dreams and serving as a mild muscle relaxant. I can attest to both of these effects: in particular, the cinchona tea seemed to loosen up my back muscles. It also gave me crazy dreams – of glowing undersea creatures made of jewels, for instance.

The second experiment was Hopestill Brett’s poppy water, the recipe for which I’ll quote in full:

A bushelle of Poppys steeped in a gallon of brandy three or 4 dayse and put into it a quarter of a ounc of Clouvs and mace half a ounc of nutmigs, 3 quarterse of a ounce of sinimon. Bett all these steepe it, stirring it often then strain it out and sweeten it to yower pallet.

Brett was clearly cooking for a large household, so I decided to use one-16th of each ingredient, and I diluted the brandy with a substantial amount of water. And since actual poppy flowers weren’t available in a cold Philadelphia winter, I used poppy seeds. The result was surprising: Brett’s water did indeed have a psychoactive effect. It wasn’t precisely what I expected. A noticeable glow of wellbeing set in around half an hour after drinking less than half the concoction, attributable to the traces of opiates in poppy seeds. But poppies also contain a number of other medicinal chemicals, including papaverine, used as an antispasmotic, and noscapine, which has been investigated as a cancer treatment. The result was a mild and pleasant but somewhat stimulating buzz.

I wondered whether Brett and her family used poppy water purely as a medicine, or whether it had a recreational element as well. Her entry gives no clues as to the drink’s uses. An 1816 book about Lincolnshire was more direct: the author found that rural cottagers in the region were avid poppy-growers who ‘had frequent recourse to [poppy water], as an inducer to stupefaction’.

At precisely the same period, Britain was building the largest empire the world had ever seen. And make no mistake, it was an empire built on the drug trade: opium, mostly, but also tea, coffee, tobacco, and what the Johns Hopkins anthropologist Sidney Mintz calls the ‘drug food’ of sugar. In Sweetness and Power (1985), Mintz argues that these new substances created systems of oppressive labour in tropical colonies that in turn fuelled the industrial nations’ labouring classes. Sugary tea, after all, was one of the main sources of calories for the typical Victorian factory worker, and sugar and rum were among the few recreations available to working folk in the era of Charles Dickens.

Yet Brett’s poppy water points to another, less well-remembered opiate of the 19th-century labouring masses: opium itself.

Lest this all seem like ancient history, it’s worth remembering that early modern drug traditions are far from dead. To use 21st-century parlance, they’ve simply been rebranded. The cutting-edge innovations of 17th-century science are now ‘traditional’, ‘alternative’ or ‘New Age’.

What replaced them? In the hands of 19th-century chemists and apothecaries, Jesuit’s powder became quinine, poppies became morphine, willow bark became aspirin, coca leaf became cocaine. What had once simply been called ‘medicine’ now became alternatives to ‘modern medicine’ grounded in these chemical transformations and syntheses of naturally occurring active principles. Yet in many ways, cures such as homeopathy are just as modern as Western pharmacy: they simply grew out of the strands of early modern learning that didn’t make it into science textbooks.

Newton or Boyle would, for instance, have found much to relate to in the theory underlying homeopathic medicines, which argues that tiny amounts of a drug can leave untraceable ‘signatures’ in sugar pills, and that poisonous plants are paradoxically effective as cures. Likewise, they’d have had no quarrel with the New Age practice of drinking minerals or metals such as colloidal silver: 17th-century medicine chests included not only ‘potable silver’, but also drinkable gold and mercury.

The clash between alternative and Western medicine might not be a clear-cut contest between ancient, ‘traditional’ remedies and modern, scientific ones

At the dawn of modern science and medicine, it was not at all clear where the boundaries ought to be drawn: foods and spices shaded into drugs, recreational intoxicants doubled as medicines, and all medicines worked by unexplainable ‘occult virtues’. The clash between alternative and Western medicine, in short, might not be a clear-cut contest between ancient, ‘traditional’ remedies and modern, scientific ones. It is a battle between two traditions that are in some ways equally modern, born out of the Enlightenment and its dark side.

Since at least the 1970s, practitioners of Western medicine have begun to pay greater heed to the flip side of their empirical tradition. Scientists have conducted experimental trials of tropical botanicals that colonial-era doctors dismissed as tools of witchcraft and 20th-century drug companies regarded as quackery. Drugs from shamanic traditions, such as ayahuasca and psilocybin (or magic) mushrooms, are also undergoing a Renaissance. Psilocybin, LSD and DMT – a psychedelic compound and the active ingredient in ayahuasca – have been tested in clinical trials for the treatment of cluster headaches, PTSD, alcoholism, and other psychiatric disorders.

In the decades to come, I suspect the lines between Western and alternative remedies will blur further still. Indeed, globalisation is already making the label ‘Western’ a bit of a misnomer. The internet, likewise, is creating new opportunities for traditional psychoactive drugs such as Polynesian kava and Southeast Asian kratom to become popular with global consumers, independent of formal channels of medical authority. More worryingly, untested new designer drugs are being synthesised from traditional botanicals by gray-market chemists in places such as China and Thailand. The infamous stimulants known to the mass media as ‘bath salts’ belong to a new class of drugs called cathinones, which turn out to be synthesised from the khat plant, a mild stimulant that has been popular in Yemen for centuries.

We can’t predict what exact synthesis between ‘Western’ and ‘alternative’ remedies will emerge in the future. But what’s for sure is that drugs will become an increasingly complex category. We’ll take high-tech pharmaceuticals for some ailments, traditional botanicals for others, and recreational intoxicants on top of both. The boundaries between these groups of drugs will continue to erode, perhaps, until they cease to exist at all. The future, in short, is beginning to look a bit like the 17th-century coffee shops of Robert Hooke’s London.