The analysis of a little-known work by the doctor Francisco Lorenzo Avilés de Aldana, proto-doctor of the army of the Duchy of Milan in the last years of the first third of the 17th century, leads us to point out his belonging to a circle of people who dealt with healthcare in Madrid, particularly interested in materia medica. After presenting some biobibliographic data on this elusive character, we analyze one of his printed texts, without date and colophon, which is justified as having been printed in Madrid in the last years of the first half of the 17th century, after his stay in Milan, and which includes within the limited production printed by this aforementioned circle of the court of Madrid.