The polyphenol content, antioxidant and antimicrobial activities of the extracts obtained by classical, ultrasonic and Soxhlet extractions from dry aerial parts of two Artemisia species (Artemisia vulgaris and Artemisia campestris) were compared. Ultrasound positively affected the yield of extractive substance and the kinetics of extraction, but the extract obtained by the classical extraction showed the highest antioxidant activities and contained higher total contents of phenolic compounds and flavonoids than the extracts obtained by two other extraction techniques. Both flavonoid aglycones (apigenin, quercetin, quercetin 3,3'-dimethyl ether) and flavonoid glycosides (rutin, hyperoside and kaempferol 3-rhamnoside) were identified by thin layer chromatograph (TLC) analysis in the extracts from both species. A. campestris extracts were richer in quercetin than A. vulgaris and its antimicrobial activity was also better than A. vulgaris. Extracts obtained from both species were found to be more effective on the tested yeasts than bacteria. The kinetics of the total extractive substances, such as phenolic, flavonoids and quercetin extraction, was successfully described by the model of unsteady-state diffusion.