Sociedade Brasileira para o Estudo da Dor c Rev Dor. São Paulo, 2011 jan-mar;12(1):35-8 SUMMARY BACKGROUND AND OBJECTIVES:The consumption of mushrooms in popular and traditional medicine is associated to immune modulating activity. It is known that decreasing the inflammatory process will decrease nociception. This study aimed at checking the antinociceptive and anti-inflammatory activity of Agaricus blazei Murill, mushroom of the sun, in Wistar rats using the modified formalin test. METHOD: Animals (n = 18) were distributed in the following groups: Control Group (CG): non-treated animals receiving just 2% Tween solvent (n = 6); Treated Group (TG): animals daily treated orally with 2.65 mg of A. blazei powder in 2% Tween solvent for 15 days (n = 12). After treatment, they were submitted to the modified formalin test. RESULTS: After formalin injection, the three phases of the formalin test were observed in CG and TG animals. The treatment with A. blazei has not interfered with formalin test phases I or II, but has decreased the number of paw elevations in phase III. CONCLUSION: The treatment with Agaricus blazei during 15 days had action in nociceptive response and acute inflammation because rats treated with Agaricus had a lower number of paw movements during phase III,