A greater understanding of the molecular mechanisms of sweet taste has profound significance for the food industry as well as for consumers. Understanding the mechanism by which sweet taste is elicited by saccharides, peptides, and proteins will assist science and industry in their search for sweet substances with fewer negative health effects. The original AH-B theories have been supplanted by detailed structural models. Recent identification of the human sweet receptor as a dimeric G-protein coupled receptor comprising T1R2 and T1R3 subunits has greatly increased the understanding of the mechanisms involved in sweet molecule binding and sweet taste transduction. This review discusses early theories of the sweet receptor, recent research of sweetener chemoreception of nonprotein and protein ligands, homology modeling, the transduction pathway, the possibility of the sweet receptor functioning allosterically, as well as the implications of allelic variation.