In this study we have investigated various morphofunctional features of gallbladder mucosa in patients with uncomplicated cholelithiasis. The histological changes, endocrine cell types and their distribution, and mucin-producing cells were characterized by immunocytochemistry and mucin histochemistry; moreover, we attempted to correlate these findings to the number and size of gallbladder stones and the type of bacteria present in the bile. Our results indicate that, despite similar clinical parameters, a wide range of histological changes can occur in the gallbladder mucosa of these patients. Moreover, the presence of certain endocrine and mucin-producing cell types in so-called "pyloric metaplasia" led us to hypothesize that this finding may be a trivial event in the gallbladder epithelium.