"In the 16th century, the procedure to prepare gold trichloride from metallic gold was well known. Paracelsus in the early 17th century, described the preparation of a red colloidal gold by reduction of gold trichloride with an alcoholic extract of plants(14 and reported that this liquid colloidal gold preparation was effective in curing diseases, improving strength, prolonging life, and rejuvenating. For melancholy, Paracelsus prescribed liquid colloidal gold because “it makes one’s heart happy.”13 Quoting from HB Weiser’s book Inorganic Colloid Chemistry published in 1933:14 “Thus around 1600, Parcelsus described the preparation of ‘Aurum Potable, Oleum Auri, Quinta Essentia Auri’ by the reduction of auric chloride with the alcoholic extract of plants, followed by the addition of sugar or syrup. The mixture, which was red in color, could be concentrated to an oily consistency without coagulating, probably because of the presence of protecting colloids in the alcoholic plant extracts used in its preparation. This aurum potable or potable gold of alchemist was supposed to have fabulous medicinal virtues curing all manner of diseases.”
If anyone is interested in understanding the roots of medicine I highly recommend reading Paracelsus's writings