The aim of this study was to determine the cadmium (Cd)-induced functional and structural changes in gastric parietal cells of male rats exposed to high Cd for 30 d. Ln the present study, control animals were fed with normal food and tap water; the remaining animals received Cd (15 ppm CdCl2) in drinking water for the same period. Receiving Cd for 30 d increased the mean blood Cd level, the mean tissue Cd content, and the mean blood pressure (p < 0.01, p < 0.001, p < 0.01, respectively). The basal acid output fell; however, the increases in stimulated acid output were not statistically significant. Light and electron microscopic examination revealed respectively that (1) Cd decreases the mean parietal eel number per unit from the control value of 23.46 +/- 3.84 to 19.46 +/- 2.12 (p < 0.05) and it affected preferentially the cells located at the distal half of the zymogenic unit and (2) in parietal cells, the Cd-induced alterations were characterized with swollen canalicular profiles, broken-down tubulovesicles, or degenerated mitochondria. We concluded that Cd augments the elimination rate of parietal cells by increasing the alteration rate and reduced basal acid output can be explained easily with the loss of parietal cell population.