Madimak (Polygonum cognatum Meissn.) plant is a wild edible plant with a cosmopolitan distribution and also traditionally consumed as food in anatolia. This study aims to optimize the extraction parameters in the pressurized liquid extraction (PLE) system and to search some beneficial properties of this plant. After the optimal extraction conditions was determined, the effect of PLE conditions on antioxidant properties was studied by using plant extracts in terms of total phenolic contents, free radical scavenging capacities and reducing power. A solvent including 1 M NaOH and water (1:99), 60 min of extraction time, 40 o C of extraction temperature and 1500 psi of pressure were optimized and found as the most productive operating conditions for PLE in the folic acid determination. Mainly, optimization of PLE conditions were carried out by considering folic acid amounts. Although antioxidant activity levels differ depending on solvent components, the similar results were obtained such in the other optimization parameters.