Two components having an immunosuppressive activity were isolated together with non-active pisolactone from Pisolithus tinctorius, and they were deduced to be 24-methyllanosta-8, 24(28)-diene-3β, 22ξ-diol and a mixture of two new compounds, (22S, 24R)-24-methyllanosta-8-en-22, 28-epoxy-3β, 28α-diol and (22S, 24S)-24-methyllanosta-8-en-22, 28-epoxy-3β, 28β-diol, respectively. Among them, pisolactone and 24-methyllanosta-8, 24(28)-diene-3β, 22ξ-diol have previously been isolated from the same mushroom. Ergosterol peroxide and 9(11)-dehydroergosterol peroxide were also isolated as active components from this mushroom in small amounts, and from Microporus flabelliformis and Lenzites betulina. The IC₅₀ values of these components were evaluated against proliferation of mouse spleen lymphocytes stimulated with concanavalin A and lipopolysaccharide.