The present paper deals with the collection and analysis of the atmospheric pollinic content in Caxias do Sul, Rio Grande do Sul, Brazil, during one year. Pollinic diagrams were used and compared with immunologic and clinicai data on 100 patients living in Caxias do Sul, who presented problems of hayfever. There appeared to be a characteristic pollinic season coinciding with the time of year when the allergic symptoms among the patients appear and are most pronounced. Thus, through the study of pollinic rain it has been possible to increase the already existing data about the occurrence of hayfever in this region
