A method has been developed for the extraction and quantitation of the ovulatory stimulant drug clomiphene from plasma. The cis- and trans-isomers were separated by normal-phase chromatography using chloroform-methanol as the mobile phase. After eluting from the column, the clomiphene was passed through a PTFE photolysis coil irradiated by a powerful UV lamp, resulting in conversion of the isomers to highly fluorescent species. The derivatised material was then detected using a fluorescence spectrometer. Use of this method enables a substantial improvement of sensitivity over UV detection and has permitted the measurement of plasma clomiphene levels in patients receiving clomiphene therapy.