A simple, sensitive and specific high-performance liquid chromatography-UV (HPLC-UV) method has been developed for the first time to simultaneously quantify the five major biologically active ingredients of saffron, namely crocin 1, crocin 2, crocin 3, crocin 4 and crocetin. Calibration curves were derived by spiking authentic compounds and internal standard, 13-cis-retinoic acid, into herbal samples prior to extraction. Extraction was conducted simply by stirring dried herb (20 mg) with 80% aqueous methanol (5 ml) at ambient temperature in the dark for 2 h. The HPLC assay was performed on a reversed-phase C18 column with linear gradient elution using methanol and 1% aqueous acetic acid. Calibrations were linear (r2 = 0.999) for all five analytes, with overall intra- and inter-day RSDs of less than 11%. The assay was successfully applied to the determination of four crocins and crocetin in three saffron samples and two Zhizi, another crocin-containing herb. Results indicate that the developed HPLC assay can be readily utilized as a quality control method for crocin-containing medicinal herbs.