The dried Mentha spicata leaves were ground in a mill and extd. with H2O, anhyd. organic solvents (MeOH, EtOH, (Me)(2)CO and CH2CN) and their 50% aq. solns. The extn. was carried out at 35 degrees C for 40 min in the presence of ultrasounds. The extracts contained 3.90-168.0 mg/100 g (in gallic acid equiv.) of phenolic coupds. and 21.3-326.2 mg/100 g (in rutin equiv.) of flavonoids. The highest yield of extn. of phenolic compds. and flavonoids was obtained in the presence of 50% aq. solns. of EtOH and Me2CO. The exts. showed an antioxidant activity as detd. with 1,1-diphenyl-2-picrylhydrazyl radical.