Chemical investigation on methanol extract of the fruiting bodies of Grifola frondosa led to the isolation of seven pyrrole alkaloids and two furanone metabolites, including two undescribed ones (compounds 1 and 3 ). The structures were established by spectroscopic data analysis and quantum chemical calculations. The absolute configuration of 2 was established for the first time on the basis of its optical rotation and electronic circular dichroism aided with quantum calculations. Compound 1 showed the suppressive activity against the cell proliferation of LPS-induced B lymphocytes with IC 50 value of 30.53 mu M and Con A -induced T lymphocytes with IC 50 value of 46.79 mu M, respectively.