As the Black Plague swept across Europe in the 14th and 15th century, claiming the lives of perhaps as much as one third of the entire continent’s population, then desperate people began turning to all kinds of madcap treatments and cures as a means of escaping the infection.

Among the seemingly endless list of supposed cures touted at the time were doses of undiluted vinegar or rotten treacle (which were perhaps meant to act as a purgative); taking low doses of toxic minerals like arsenic and mercury; avoiding bathing in clean water (which was believed to weaken the heart) and instead bathing in sewer water; whipping or self-flagellation (as ill-health was seen as a curse from God that required penance); burning off a bubonic fever by sitting as close to a fire as could be tolerated; strapping chicken carcasses to infected areas of the body (which was believed to draw the infection out into the bird); and even rubbing chopped onions, snake entrails, or pigeon guts onto an infected person’s body.

If none of these take your fancy, of course, there’s always the considerably more pleasant use of posies of fragrant flowers and herbs, often including cloves and rose petals, known as nosegays, which were worn around the neck or in front of the fact to ward off infection. Long before medical science found out the true cause of the disease, many Tudor English physicians (like those long before them) believed that bad smells and musty air must doubtless be the cause of infection and ill health. So they reasoned that breathing through more pleasant and fragrant material was a surefire way of protecting oneself from diseases.

As misguided as all of these cures were, however, smelling a posy of flower or ingesting treacle is a lot more pleasant than a cure that the physicians of London came up with when the city was struck by a further of the outbreak plague in the 17th century.

More than 200 years after the first outbreak in the medieval era, cases of the bubonic plague began to reappear in London and across England in the mid-1500s. By the turn of the century, the situation had worsened to such an extent that the city was forced to essentially go into lockdown, closing many public areas and businesses to stem the steady flow of infections through the population. Famously, it was this resurgence of the plague that forced the closure of Shakespeare’s beloved Globe Theatre in 1603.

With the precise cause of the plague still unknown to physicians at the time, yet with many still believing it to be due to inhaling fetid air, doctors across London fell back on old preventative methods and quack cures to attempt to stop the disease. But some, now aware that the earlier posies and nosegays had provided little real protection from the infection, came to a contrary conclusion. If pleasant smells had not held the plague at bay, they reasoned, then perhaps the opposite was true: If a patient could dilute the foul air of the plague with an equally unpleasant aroma, perhaps that would counter the disease’s course? It seemed like a perfectly sound idea at the time; and, for that matter, a perfectly simple theory to test, given that everybody has a source of foul-smelling air attached to their person. Put another way: yes, the plague doctors of 17th-century England really did encourage people to smell their own farts!

They went even further than that. Believing that foul air could drive out a foul infection, the doctors encouraged Londoners to break wind into glass bottles and jars, which they could then keep at home or on their person. As soon as they felt unwell, or believed themselves to have become infected with the plague, the doctors proscribed a quick whiff from the patient’s jar of farts as a means of boosting their immunity and seeing off the disease.

Needless to say, the theory did not work. The plague continued to ravage London for another 50 years, until ironically the Great Fire of 1666 helped stem the flow of infections across the city once and for all.