The chemiotopical organization of the human primary gustatory cortex (GI) in the fronto-parietal operculum was studied in 15 healthy subjects (10 women, 5 men) by applying five taste stimuli (salty, sweet, sour, bitter, neutral) to either side of the tongue (2-5 stimuli/subject) using a 5-min fMRI block design protocol that envisaged alternate periods of rest and stimulation. The protocol was approved by the local Ethics Committee. Data were analyzed with the BrainVoyager software. Unilateral tongue stimulation consistently evoked bilateral activation in area GI. Ipsilateral foci were generally larger and signal increases greater. The foci evoked by each tastant exhibited slightly but not significantly different mean Talairach coordinates, broad overlap and high interindividual variability; the salty stimuli generally evoked more anterior foci and bitter stimuli more posterior activation. These data confirm that the gustatory pathways from tongue to cortex are bilaterally distributed, with an ipsilateral predominance. Although distinct GI zones were activated by the different taste stimuli, a clear topographical organization could not be recognized. Possible explanations are that the fMRI technique is unable to resolve fine topographical arrangements or that the discriminative role of area GI for different tastants is subserved by a different mechanism. However, both explanations may also apply.