The oldest known medical plants-related data and their use for the purpose of treatment were found in medicine of ancient civilizations. Pharmacognosy, the study of drugs isolated from natural sources, finds its roots in the civilization of ancient Greece. The monasteries had important role for the european middle ages medicine, in which the classic Greek-Roman manuscripts were copied by hand. The Salerno School of Medicine was founded and developed under the Arabic influence, carried by the trade routes to the east. It's most known medical work was Flos medicinae: Regimen sanitatis Salernitanum, which is a rulebook of healthy lifestyle, ilnesses, and plant-based drugs, based on the classical sources and empiric experience of doctors of Salerno. Originally written in Latin, later it was translated to Croatian by a Francisian monk Emerik Pavić (1768.). It was the first medical book in Croatian language. This diploma thesis gives insight in thirteen plant-based drug recipies from Flos medicinae, of those plants that grow in the local area: plum, fig, fennel, anise, marsmallow, peppermint, sage, common rue, onion, white mustard, common nettle, greater celandine, and willow. This diploma thesis gives insight into the ATC classification of some of the selected plants, because many of those drugs are still in use in the modern phytotherapy.