Ilex paraguariensis is a native plant from Southern America, where it is used as a beverage. In traditional medicine, it is used to treat many diseases including inflammation. However, we do not yet know precisely how this effect occurs. We therefore evaluated its anti-inflammatory effect in a murine model of pleurisy. The standardized CE, BF and ARF fractions, Caf, Rut and CGA were able to reduce leukocyte migration, exudate concentration, MPO and ADA activities and NOx levels. Moreover, I. paraguariensis also inhibited the release of Th1/Th17 pro-inflammatory cytokines, while increasing IL-10 production and improving the histological architecture of inflamed lungs. In addition, its major compounds decreased p65 NF-κB phosphorylation. Based on our results, we can conclude that I. paraguariensis exerts its anti-inflammatory action by attenuating the Th1/Th17 polarization in this model. This fact suggests that the use of this plant as a beverage can protect against Th1/Th17 inflammatory diseases.