PURPOSE: To investigate the in vivo proton MR spectra of the bile of human gallbladder in its normal and diseased states and to compare the findings between the two groups. MATERIALS AND METHODS: In vivo proton MRS was performed in 88 subjects comprising 33 healthy volunteers, 41 patients with gallstone, and 14 with distal common bile duct obstruction. For this, a clinical 1.5T system with a body coil and STEAM (STimulated Echo-Acquisition Mode) was used. We analyzed the MR spectra of normal and diseased gallbladder biles and tried to categorized the findings according to the significant peaks occuring within consistent ranges of chemical shift. We also compared the spectral patterns between normal and dis-eased bile. RESULTS: Proton MRS showed four significant major peaks in normal and diseased human bile: peak 1 at 0.8 - 1.4 ppm, peak 2 at 3.2 -3.4 ppm, peak 3 at 3.9 -4.1 ppm, and peak 4 at 5.2 -5.4 ppm. In each group, peak 1 was most frequent(healthy volunteers, 91%, patients with gallstone, 100%, patients with distal common bile duct obstruction, 93%), but as compared with normal bile (peak 2, 36%, peak 3, 33%), in patients with gall-stone, peak 3 was more frequently seen (46%), and in those with distal common bile duct obstruction, peaks 2 (64%) and 3 (64%) were most frequent. According to the significant peak, each MR spectra was categorized as follows: pattern I: peak 1; pattern II: peaks 1 and 2; pattern III: peaks 1 and 3; pattern IV: peaks 1, 2, and 3; pattern V: peaks 1 and 4; pattern VI: peak 3. In normal bile, the common MR spectral patterns were I (36%), II (27%), III, IV, VI, and V, in decreasing order of frequency. In patients with gallstone, however pattern I (44%) and pattern IV (34%) predominated, while in those with distal common bile duct obstruction, pattern IV (57%) CONCLUSION: The spectra of normal and diseased gallbladder bile obtained by in vivo proton MR spectroscopy varied, with some differences in spectral patterns between both groups.