Medical quacks

Quack is an abbreviation of quacksalver, an old word borrowed from the Dutch, kwakzalver. The term ‘quack’ meant ‘shouting’ in the Middle Ages so a kwakzalver was someone who shouted about salves; i.e., a “hawker of salve”. Quacksalvers sold their salves, oils and balms in marketplaces and at town fairs by loudly proclaiming the miraculous effects of their products.