It was the famous medieval German physician Paracelsus who first prepared colloidal gold solution in modern times. He called his gold purple solution "Aurum Potabile" (Drinkable Gold). After studying the work of Paracelsus, the English chemist Michael Faraday prepared the first sample of colloidal gold in 1857, and many uses were found for his solutions of “activated gold". As 20th century medicine developed, gold disappeared from pharmacopoeias, except in the case of rheumatoid arthritis. As for the possible biological role of gold as a trace element, the question has only recently been explored.