Mustard was one of the earliest products to be used in folk medicine. In the Middle Ages, war wounds were often treated by applying a layer of Maille mustard mixed with crayfish powder.

During the great yellow fever epidemics along the banks of the Mississippi that brought about thousands of deaths, mustard sold for the price of gold. Stocks soon ran low in the supply stores since it was believed that mustard offered protection against the terrible illness.

In the 17th century, the vinegar maker Maille distributed mustard to the poor of Dijon to help protect them from chillblains.

Even in the 6th century BC, the Greek scientist Pythagoras recognized the importance of mustard poultices as an antidote to scorpion bites. It was thought that it takes one demon to drive another demon out, and mustard, by irritating the skin, expelled the poison.

Similarly, during the Italian Renaissance, when poison was considered the perfect method for doing away with anyone who stood in the way of love, money or honour, mustard was used as an emetic. It was taken if stomach cramps were felt after eating or drinking, since you never knew if some malevolent hand had added a few drops of a concoction intended to send you to your eternal reward. Although most unpleasant to take, this remedy nonetheless saved many lives and is still used in traditional medicine.

A century after Pythagoras, Hippocrates prescribed a vast number of mustard-based antidotes.

In the Faroe Islands, a plaster was made with powdered mustard seeds and placed on the cheek to alleviate toothache. The oil contained in the mustard seed is edible but it is mostly used in making pharmaceutical products, soap, leather and wool articles.