P. ostreatus mushrooms were able to absorb and accumulate Se when selenite was used for enrichment. The Se content was proportional to the amount of sodium selenite added to the substrate. The lowest concentration tested resulted in mushrooms with 57.6 mgkg1 of Se in the dry matter by Gaso et al. In 15 species of mushrooms collected in nature, which varied from 0.38 to 8.42