We use ultraviolet data, acquired with a photodiode-array detector coupled to a reversed-phase liquid-chromatographic system, to identify unknown drugs in plasma samples of acutely poisoned patients. Both retention time and spectra of the peaks obtained with a microbore Hypersil ODS column under gradient elution are compared with a library of approximately 350 compounds. We present our three-year experience with this system, which identifies drugs in less than 1 h, with a high degree of confidence.