Anti-inflammatory effect of ethanolic extractions of Pleurotus ostreatus would measure on body temperature and the C-Reactive protein (CRP) in rats induced by carrageenan. In this study, 30 rats were divided; group I (normal control) group II (negative control- caraggenan), group III (positive control- ibuprofen 400 mg / time), group IV and V (treatment I and II: ethanolic extract at 250 and 500 mg / kg BB). The Rats’ body temperature was measured at 0, 2, 4, 6 hours and at the 6th hour the qualitative and semiquantitative CRP was examined. The results showed that the temperature was reduced in the 1st to 6th hour, with different patterns. The Kruskal Wallis test shows significant P-values in the 2nd hour (0.02) and 6th (0.02). The qualitative CRP was analyzed using the Fisher Test and showed a significance at 1:2 dilutions (p=0), while the semiquantitative CRP is only at 1: 1 a dilution (p=0.0). The ethanol extraction of Pleurotus ostreatus at the dose of 250 mg and 500 mg / Kg BB showed a decrease in temperature and CRP, which was quite good when compared with ibuprofen. This result confirms about anti-inflammatory effect of the mushroom.