The aim of the work was to compare the microwave-assisted extraction of coriander, black cumin and milk thistle seeds with the conventional process of extraction. Before the extraction material was crumbled, sieved and defatted. Obtained extracts were analyzed by means of the content of the antioxidants using ABTS, DPPH, Folin - Ciocalteu methods as well as the content of silibinin by HPLC (in case of milk thistle). By using these methods the content of reducing compounds, ability to scavenge free radicals and antioxidant capacity was evaluated in each case. It was shown that for the black cumin and milk thistle more effective was microwave extraction, but for the coriander conventional seems to be better. Extracts of black cumin and milk thistle obtained by microwave extraction have higher concentration of antioxidant compounds as compared to extracts from coriander. In case of coriander most effective a conventional extraction have been designated as more effective one.