The present study was conducted to determine the content of pharmacologically important constituents hypericin, pseudohypericin, chlorogenic acid, rutin, hyperoside, apigenin-7-O-glucoside, quercitrin, quercetin and vitexin in eight Hypericum species namely, H. aviculariifolium Jaup. and Spach subsp. depilatum (Freyn and Bornm.) Robson var. depilatum (endemic), H. lydium Boiss., H. montbretii Spach, H. orientale L., H. origanifolium Willd, H. perfoliatum L., H. perforatum L. and H. pruinatum Boiss. and Bal. growing in different locations of Turkey. Wild growing plants were harvested at flowering and after dried subsequently assayed for the constituents by HPLC method. Hyperoside, quercitrin and pseudohypericin were found in all species. Hypericin, quercetin and chlorogenic acid were also detected in all species with the exceptions of H. orientale for hypericin, H. montbretii for quercetin and H. lydium for chlorogenic acid. Apigenin-7-O-glucoside accumulation was observed in all examined species at various levels, except for H. orientale and H. origanifolium. Rutin was detected in H. aviculariifolium, H. lydium, H. orientale, H. perfoliatum and H. perforatum. On the contrary of the other species, vitexin was found in only H. motbretii. The presence of flavonoid vitexin in the genus Hypericum was reported for the first time.