Joseph Andreas Jacobus Plenck was born in 1735 in Vienna where he studied surgery with Johan Christian Retter. At age 35 he was appointed Professor of Surgery and Obstetrics by Maria Theresia. Subsequently he became professor and life long secretary of the Medical Military Academy know as the Josephinum where he worked up to 1807. He was one of the most brilliant scientific writers of his time. Here we analyze his medical treatise, Icones Plantarum Medicinalium secundum systema Lynnaei cum enumeratione virium et usus medici, chirurgici et diaetetici, published in folio in Latin and German. This is a therapy based on plants in which the author discusses the medical use of 758 plants. This article is centered on 111 plants with diuretic properties which still appear in many pharmacopoeias.