The 4 thieves vinegar

The 4 Thieves is a real potion surrounded by legends say so:
At the moment of the big plague, four thieves were invading contaminated homes, with impunity and berthed the dying. Never succumbed to evil despite taking risks. They were finally taken by the authorities and were sentenced to death. They were given life in exchange for the formula of this mysterious liquid that rubbed and drank before acting to immunize.