the history of plant’s used for mankind is as old as the start of humankind. initially, people used plants for their nutritional proposes but after the discovery of medicinal properties, this natural ?ora became a useful source of disease cure and health improvement across various human communities. berberis vulgaris is one of the medicinal plants used in iranian traditional medicine. berberis vulgaris (barberry) belongs to the berberidaceae family and various parts of this plant including its root, bark, leaf and fruit have been used as folk medicine for long in iran. several properties such as antibacterial, antipyretic, antipruritic and antiarrhythmic have been studied previously. most of these properties are due to the presence of some alkaloids;berberine and palmatine and oxicanthineetc. plants are considered the most important source of alkaloids therefore, investigating the presence of alkaloids in different plants is very important.the berberis root sampling is done in mid-autumn (the fruiting time)from the chaharmahal and bakhtiary zagros mountains. the samples were dried in dark room at ambient temperature. after grinding to appropriate size, different solventincluding; ethanol, methanol and acetonitrile,were used. the extraction of bioactive compounds from samples were accomplished by ultrasonic assisted extraction. the hplc method was used to estimate the amount of extracted constituent in different extractant solvents.optimization of the extraction conditions were performed using design of experiments approach. the effect of different parameters on extraction including acetonitrile/methanol presence, concentration of hcl and water presence, were optimized by applying a rotatable central composite design (ccd) and response surface methodology. the obtained optimized extraction factors are: 83:8% (v/v) of acetonitrile/methanol, 8% of water, 1.5% hcl, time 20 (min)and temperature 40?c.