Functional assays for identifying compounds that activate or modulate the activation of the T1R2/T1R3 (sweet) taste receptor are provided. These assays detect the effect of one or more compounds on the activation of T1R2/T1R3 (sweet) taste receptor or on the activation of T1R2/T1R3 sweet taste receptor by another, compound e.g., saccharin or another artificial or natural sweetener. These assays preferably are cell-based functional assays and typically use cells, e.g., HEK-293 cells that stably express a G protein such as G.sub..alpha.15, G.sub..alpha.16 or gustducin. Compounds identified in the disclosed functional assays are potentially useful as additives in compositions for human or animal consumption.