Blue mass

Blue mass (also known as blue pill or pilula hydrargyri) was the name of a mercury-based medical treatment for syphilis common from the 17th to the 19th centuries. The oldest formula is ascribed to one Barbarossa, in a letter to Francis I of France.[1]

  1. ^ Frazer, William. Elements of Materia Medica. Dublin, 1851, p. 173.