In the present investigation methanol and acetone extracts of basidiocarps of mushrooms Laetiporus sulphureus and Meripilus giganteus were evaluated for their antimicrobial, cytotoxic and antioxidant/prooxidant effects. The antimicrobial potential was determined by the microdilution method against ten microorganisms. Cytotoxic effects were evaluated by MTT test, while changes of the redox status parameters (superoxide anion radical, nitrites and reduced glutathione) were determined spectrophotometrically on a human colorectal cancer cell line and human health fibroblasts cells. The results were measured 24 and 72 h after the treatment. Tested extracts exhibited moderate antimicrobial activity with MIC values from 0.004 to 20 mg/mL. The maximum antimicrobial activity was found in the methanol extracts of the M. giganteus against Bacillus subtilis, which was better than positive control. The acetone extract of M. giganteus with IC5072h = 13.36 μg/mL showed significant cytotoxic effect with strong cell selectivity (selectivity index = 37.42) against cancer human colorectal cancer cells. The tested extracts, especially M. giganteus acetone extract, induced an increase in oxidative stress parameters in tested cell lines, but significantly heightened it in human colorectal cancer cells. The obtained results suggest that these extracts, especially M. giganteus acetone extract, can be proposed as a novel source of nutraceuticals and pharmaceuticals.