Dandelion is a sustainable biomass that has occasional use in the food and pharmaceutical industry. However, commercial use of its extracts is restricted by the lack of systematic information on safety, composition, and biological activity. To broaden dandelion use, the present study brings new knowledge on extracts from dandelion seeds that could find application as safe and functional food ingredients. The employed two-step supercritical fluid extraction process, followed by the conventional extraction, enabled the separation of extracts with increased content of phenolics, tocopherols, and essential fatty acids. Those compounds were found to be the major components of dandelion extracts, reaching high values up to 799 mg GE/g, 249 mg α-TE/g, and 75%, respectively. The extracts also contained significant amounts of flavonoids (up to 20.5 mg QE/g) and pigments (chlorophyll A up to 1.0 g/kg, chlorophyll B up to 0.3 g/kg, and carotenoids up to 0.1 g/kg). This study revealed new bioproducts that express strong antioxidant (reaching IC50 values up to 132.5 μg/mL) and antimicrobial activity (with minimum inhibitory concentrations up to 80.0 μg/mL). Among the tested 23 microbial strains, the extracts exhibited the strongest activity against food-borne pathogens Micrococcus luteus and Bacillus subtilis. Furthermore, the antitumor and antiviral activity of separated dandelion biological products was evaluated. Keywords: Bioactive compounds,Chemical composition,Functional food ingredients,Supercritical CO2 extraction,Sequential extraction process Valorization