In the present study, we evaluated the effectiveness of a new infusion set equipped with an in-line filter (5μm pore size) in removing precipitates of foreign matter forming during or after the preparation of infusion fluids. We also examined the ability of the new infusion set to prevent adverse effects associated with the intravenous injection of fluids containing crystalline precipitates in rats. The number of particles and their sizes were measured for two infusion fluids administered using a conventional infusion set without an in-line filter and the new infusion set, collecting the samples for measurement from the outlets of the respective infusion sets. One of fluids was a glycyrrhizin solution prepared from a glass ampoule injection, and the other etoposide solution prepared by diluting a preparation of this solution in a vial with saline. A number of particles (>10μm in size) were detected for both infusion fluids when administered by the conventional infusion set but none were detected in them when administered by the new infusion set. The intravenous injection of the precipitate-containing etoposide solution from the conventional infusion set to rats caused marked extravasation of plasma proteins and edema in lungs. Such adverse reactions did not occur with the new infusion set, demonstrating that it was effective in removing particulate matter. It should thus be useful in intravascular fluid therapy from the safety point of view.