Vinegar of the Four Thieves: On Plague Preparations and Survival
Four thieves were arrested in Marseille in 1722 and should, by every reasonable expectation, have been dead. They were not. What they carried — a vinegar preparation steeped with wormwood, rue, rosemary, and thyme — is one of the oldest documented herbal formulas in the Western record. A history of the preparation, its herbs, and how to make it.
Four thieves were arrested in Marseille in 1722 and should, by every reasonable expectation, have been dead.
The plague had arrived two years earlier on a merchant ship — Le Grand Saint-Antoine, which should have observed its quarantine and did not. By the time the thieves were caught looting the homes of the dead, the disease had taken fifty thousand lives. Half the city. The streets of Marseille were simultaneously a medical catastrophe and a criminal opportunity, and these four men had found the overlap between them.
They were alive. They were healthy. When they were brought before the magistrate, he reportedly offered a choice: hang, or speak.
They spoke.
The Formula
The magistrate had the preparation posted publicly. One version — drawn from a 1722 posting at the Hôtel de Ville, preserved in a French pharmacopoeia — reads roughly:
Take three pints of strong white wine vinegar. Add a handful each of wormwood, wild marjoram and sage, fifty cloves, two ounces of campanula roots, two ounces of angelica, rosemary and horehound, and three large measures of camphor. Infuse all these in the vinegar for fifteen days, strain, and bottle. Use by rubbing the hands, ears and temples before approaching the sick.
This is one of at least seven distinct formulations attributed to the same story — which tells you something about how legends multiply and how recipes drift in transmission. But across all versions, the same plants appear. Wormwood. Rosemary. Rue. Thyme. Lavender. Garlic. What the thieves reached for was not random.
What They Were Protecting Against
The plague that killed Marseille was Yersinia pestis — the same organism responsible for the Black Death, the Justinianic Plague, the Third Pandemic. It travels primarily by the bite of infected fleas, which arrive via rats, which reach humans in conditions of crowding and poor sanitation. The miasma theory that dominated eighteenth-century medicine — the belief that disease spread through corrupted air — was wrong about the mechanism but not entirely wrong about the response. Aromatic preparations that repelled the smell of decay also repelled, to some degree, the insects carrying the pathogen.
The four thieves may not have known this. They knew that the dead were dangerous and that smell had something to do with it. They knew, from somewhere — inherited knowledge, an apothecary's instruction, their own observation — that certain plants could be held between them and the dying.
They were not wrong.
The Herbs
The plants that appear consistently across versions of the formula share a quality: high concentrations of volatile aromatic compounds with documented antimicrobial activity.
Thyme contains thymol — a phenolic compound that remains in active use as a pharmaceutical disinfectant and antiseptic. It is the active ingredient in some clinical mouthwashes. The folk tradition preceded the chemistry by roughly two thousand years and arrived at the same conclusion.
Rosemary carries rosmarinic acid and camphor, both antimicrobial. In the Mediterranean tradition, rosemary was scattered on floors and hung above doors not as decoration but as fumigation. That practice had genuine epidemiological logic, understood entirely without the vocabulary of epidemiology.
Lavender appears in every version of the formula. Its primary volatile oil, linalool, is well-documented as antimicrobial and antifungal. The lavender at a threshold was not only aesthetic.
Wormwood has been used against pest and pathogen since antiquity. The compound thujone, which gives wormwood its distinctive bitterness, is genuinely antimicrobial and has been used historically to repel insects — including fleas. This is not coincidence. Wormwood knows what it is for.
From the Conservatory
Wormwood
Artemisia absinthium
Bitter before all else. Then the other things begin.
The thujone content that makes wormwood effective also makes it dangerous in concentrated internal use. In a vinegar preparation used externally — or as a diluted tonic — the concentrations are well within safety margins.
View entry in the Conservatory →Rue is the most ambiguous of the formula herbs and the most interesting. It appears in protective preparations across the Mediterranean not primarily for its antimicrobial properties but for its long association with warding — a quality that resists quantification but is recognisable in the record once you know what to look for. In the Four Thieves formula, rue is the plant that says: something that means harm is present, and this preparation has been made in answer to it.
From the Conservatory
Rue
Ruta graveolens
The herb of grace. The herb of repentance. The herb of things left unsaid.
Rue is a photosensitiser — the furanocoumarins in fresh rue cause burns when exposed skin meets sunlight. A diluted vinegar preparation used and washed off poses minimal risk, but avoid applying to skin before going into sun.
View entry in the Conservatory →Making It
This is a cold infusion — the herbs steep in vinegar rather than being cooked, which preserves the volatile oils that heat would drive off. Apple cider vinegar is the appropriate base; its acidity and its own mild antimicrobial properties are part of the preparation.
What you need:
- 500ml raw apple cider vinegar (with the mother, if you can find it)
- 2 tablespoons dried rosemary
- 2 tablespoons dried thyme
- 2 tablespoons dried lavender
- 1 tablespoon dried wormwood
- 1 tablespoon dried rue
- 1 tablespoon dried sage
- 6–8 cloves of garlic, roughly crushed
- 10–12 whole cloves (the spice)
- 1 teaspoon black peppercorns
Combine all herbs and garlic in a clean glass jar with a non-metal lid — metal corrodes in vinegar. Pour the apple cider vinegar over, ensuring all plant material is submerged. Seal and leave to infuse in a cool, dark place for four weeks, shaking daily. Strain through cheesecloth, pressing all liquid from the herbs. Bottle in dark glass.
The finished vinegar keeps indefinitely at room temperature. It improves with time.
Use: rub diluted onto the skin before exposure to crowded or potentially infectious environments; add to bathwater; take one tablespoon to a cup of water as a general tonic — the taste is assertive and medicinal and bitter, not unpleasant to those who develop a palate for preparations that taste like they mean something.
On What This Is Not
It is not a cure for plague.
The four thieves survived as much through luck and the particular aerobiology of their exposures as through their preparation. The Marseille plague was primarily pneumonic in its later stages — spread person to person through respiratory droplets — and no herbal vinegar rubbed on the hands prevents the inhalation of a pathogen.
What it is: a preparation with genuine antimicrobial properties, with a specific and documented history of being reached for in extremity. A bitter, aromatic tonic that the body recognises as medicine because several of its ingredients are, in the chemical sense, precisely that. An old agreement between people and plants about what to do when the dying season comes.
The exact mechanism can be argued. That four people carried it through the worst epidemic in eighteenth-century France, through streets full of bodies, and emerged alive — that is in the record.
They knew something. The something was botanical.