four thieves' vinegar

From the story that thieves, by using it, were enabled to plunder, with impunity to health, in the great plague at London. Possibly originally a corruption of "Forthave's vinegar", Richard Forthave being the publisher of an early recipe.

four thieves' vinegar (uncountable)

1. (UK, archaic) Vinegar mixed with camphor and essential oils, formerly used as medicine.

• Marseilles vinegar
• thieves' vinegar