GHB is a central-nervous-system depressant that has sedative and amnesic effects at higher doses. There has been a significant increase in the need to examine the presence of GHB in liquids that may have been secretly spiked by persons with the intent that they be ingested by persons who would subsequently be physically helpless in resisting a sexual assault and unlikely to have a clear memory of the attack. The detection method described in this paper used solid-phase microextraction (SPME) to extract GHB from liquid samples, followed by on-fiber derivatization and analysis by gas chromatography/mass spectrometry. GHB was spiked into several beverages (coke, beer, lemonade, and water) at a concentration of 100 ppm, and the solutions were analyzed with the method described. A high yield of derivatized GHB was achieved for the extraction from all of the spiked beverages. The total ion chromatograms for the spiked beverage analyses were more complex than from pure water; however, when ion 233 m/z was extracted, a clean spectrum was obtained for all beverages. GHB was detected with good sensitivity, high precision, excellent linearity from 0.01 mg/ml to 0.25 mg/ml, and without the need for sample manipulation that could cause interconversion between GHB and its lactone, GBL. 7 figures and 23 references