Tetrahydro-beta-carbolines (THCs), potential neuroactive alkaloids, were found in chocolate and cocoa. 6-Hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline (6OHMTHC), 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (THCA), 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) in both diastereoisomers (1S,3S and 1R,3S), and 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTHC), besides serotonin and tryptamine biogenic amines, were identified and quantified in dark chocolate, milk chocolate, cocoa, and chocolate-containing cereals by RP-HPLC-fluorescence and HPLC-MS. For each THC, the concentration ranges were determined: 6OHMTHC (0.16-3.92 g/g), THCA (0.01-0.85 g/g), 1S,3S-MTCA (0.35-2 g/g), 1R,3S-MTCA (0.14-0.88 g/g), and MTHC (nd-0.21 g/g). The highest content was generally found in chocolates and cocoas, but cereals containing chocolate also showed an appreciable amount of THCs.