: The Italian botanist Arturo Nannizzi (1887-1961) and his contribution to the treatment of parkinsonism following encephalitis lethargica.

We describe the Italian contribution to the description and treatment of parkinsonism following encephalitis lethargica (EL): postencephalitic parkinsonism (PEP). Special attention is devoted to the description of postencephalitic symptoms by Giuseppe Panegrossi (1871-1953) and to the treatment based on introduced in Italy and extensively supported by Arturo Nannizzi (1887-1961), who was charged by the queen of Italy with conducting research into this plant and advocating its cultivation for healing purposes. This article gives us the unique opportunity to revisit the figure of this distinguished botanist, providing a summary of his biography, interests, and achievements.