This article questions the belief expressed in various histories of pharmacy that the tenth-century Arab physician Avicenna introduced the tradition of coating pills with gold and silver. Although an examination of his Canon documents Avicenna's interest in the medicinal application of gold and silver, no mention is made of coating pills. Nor do other Islamic physicians seem to have been familiar with this practice, any more than such medieval European authors as Arnaldus of Villanova, Raymund Lull or Johannes de Rupescissa. The same is true of medicinal compendia representative of later periods, such as the Ortus sanitatis, Valerius Cordus' Dispensatorium or the Secrets of Alessio Piemontese. The earliest known mention of coating pills with precious metals occurs in a non-medical book, The Golden Fleece (London, 1626), and the earliest mention in the professional literature seems to appear only in the second half of the seventeenth century. The practice of coating pills with gold and silver was to be practiced in Europe into the first half of the twentieth century.