Tetrahydro-~-carboline-3-carboxylicacid (THBC-3-COOH) and l-methyltetrahydro-P-carboline-3carboxylic acid (1-MeTHBC-3-COOH)were identified and quantitated in beer and wine. The analytical procedure employed aqueous derivatization with methyl chloroformate to facilitate the isolation, to improve the liquid chromatographic separation, and to eliminate the potential for artifactual formation of these compounds during sample preparation. Identification and quantitation were accomplished through a combination of high-performance liquid chromatography and mass spectrometry. The concentration of THBC-3-COOH in beer and wine ranged between 2.7-10.9 and 0.8-1.7 pg/mL, respectively, and the concentration of 1-MeTHBC-3-COOH ranged between 0.3-4.2 and 1.3-9.1 pg/mL, respectively.