Before anyone knew germ theory, our ancestors assumed that a bad smell was not only the symptom of a disease, but the cause itself. For centuries, they turned to sweet fragrances and strange machines to stay healthy.

The Early Science Of Disease

Found SF

In the Middle Ages, educated men were scrambling to figure out why the Black Death was wiping out hundreds of thousands of people across Europe and the Middle East.

Naturally, they used the symptoms of the plague as clues to its cause. They came up with miasma theory, the idea that pestilence is carried by unclean air.

The Malignant Fog


Many people even thought that the "maismas" in the air were magical, and that there was a bigger chance of getting sick if there was fog over the city or a swampy atmosphere since the pestilence in the air was blown in on the wind.

In ancient China, disease was thought to revel in heat and moisture, and it polluted fog, water, and trees through the waste of insects.

Plague Doctors


Plague doctors were hired by cities in the 14th century. They treated both rich and poor victims of the Bubonic plague and wore bird-like masks filled with aromatic herbs and flowers.

These healers were usually not professionally-trained doctors. They practiced bloodletting and rarely actually cured anyone.

Plague doctors were usually the only people allowed to perform autopsies, a taboo in Medieval Europe, making them all the creepier.

Teeming Cities

Wikimedia Commons

Very popular in England, the miasma theory was "supported" by the rapid industrialization and growth that led to crowded and dirty streets—a breeding ground for infectious diseases.

In the summer of 1858, in London, the hot July air near the River Thames was sticky with the smell of untreated human waste and industrial effluent. There was a common belief that the stillness of "night air" made going outside in the dark especially risky.

The Great Stink

British Museum

The city's sewer system emptied into the river, and huge outbreaks of cholera were blamed on "The Great Stink."

When the city made efforts to fix the housing and sanitation issues, people seemed to get healthier, so it reinforced the false connection between bad smells and sickness.

Sweet Smells As Medicine

Wikimedia Commons

Pomanders were bags, vases, or ball containers containing fragrant herbs, oils, and other early forms of aromatherapy.

Pomanders were usually owned by wealthy people, who put them up to their faces when walking by a bad smell.

Memento Mori

Science Museum

Like pomanders, vinaigrettes like this one could hold oils and fragrances. They were usually hung on chains around the body.

The scents were inhaled from a vinegar-soaked sponge in the small container through holes on the top.

The smell of vinegar also supposedly stopped people from fainting.

The Fumigation Machine

Wikimedia Commons

Around 1770, the physician Pierre Lalouette thought that he had made a breakthrough in the treatment of venereal disease with his smell-producing fumigation machine.

The machine burnt a combination of frankincense, nutmeg, myrrh, juniper, and sulphur.

Noxious Air


The name of the disease Malaria came from 'mal aria' or 'bad air' in Medieval Italian.

The idea that unhealthy air caused malaria instead of infectious mosquitoes came from the Ancient Romans. They hypothesized that malaria originated in the fumes of swamps and took the form of a poisonous mist.

Florence Nightingale

Wikimedia Commons

A Victorian celebrity and the founder of modern nursing, this Crimean War nurse lived from 1820 to 1910.

Nightingale was a fan of miasma theory and worked hard to make sure that the hospitals she was in were clean and smelled good in order to preserve a "pure air."

The End Of Miasma Theory

Wikimedia Commons

Even though it was ultimately wrong, the miasma theory did encourage scientific interest in decaying matter, cleanliness in hospitals, and, after centuries, the proper identification of microbes as the causes of disease.

Germ theory was proposed by Girolamo Fracastoro in 1546, but it was only scientifically accepted in the late 1800s due to the efforts of Louis Pasteur and Robert Koch. Viruses were discovered in the 1890s.