Purpose:Echinacea purpurea(L.) Moench is a member of theAsteraceaefamily and is traditionally used mainly due to its immunostimulatory properties. Various compounds including alkylamides and chicoric acid were reported as active ingredients ofE. purpurea. Here, we aimed to prepare electrosprayed nanoparticles (NPs) containing hydroalcoholic extract ofE. purpureausing Eudragit RS100 (EP-Eudragit RS100 NPs) to improve the immunomodulatory effects of the extract.Methods:The EP-Eudragit RS100 NPs with the different extract:polymer ratios and solution concentrations were prepared using the electrospray technique. The size and morphology of the NPs were evaluated using dynamic light scattering (DLS) and field emission-scanning electron microscopy (FE-SEM). To evaluate the immune responses, male Wistar rats were administrated with the prepared EP-Eudragit RS100 NPs and plain extract in the final dose of 30 or 100 mg/kg. The blood samples of the animals were collected and the inflammatory factors and complete blood count (CBC) were investigated.Results:In vivostudies indicated that the plain extract and EP-Eudragit RS100 NPs (100 mg/kg) significantly increased the serum level of tumor necrosis factor-α (TNF-α) and interleukin 1-β (IL1-β) whereas the EP-Eudragit RS100 NPs (30 mg/kg) significantly increased the number of white blood cells (WBCs) compared to the control group. Lymphocytes’ count in all groups was increased significantly compared to the control group (P<0.05) whereas other CBC parameters remained unchanged.Conclusion:The prepared EP-Eudragit RS100 NPs by electrospray technique caused significant reinforcement in the immunostimulatory effects of the extract ofE. purpurea.