To obtain information about the effects of lenticular polyols on the prevention, initial stages, and development of diabetic cataracts, we identified and determined with gas-liquid chromatography or gas-liquid chromatography/mass spectrometry eight polyols in cataractous lenses of non-insulin-dependent diabetes mellitus patients and nondiabetic subjects. In the diabetics' lenses, the concentrations of polyols (e.g., sorbitol, fructose, mannitol, and adonitol) were higher than in the nondiabetics' lenses, whereas the concentration of 1-deoxyglucose was lower. The mean concentration of myo-inositol in lenses of diabetics was lower than that of nondiabetics, but this difference was statistically not significant. The total content of eight polyols in the diabetics' lenses did not differ significantly from that in the nondiabetics. In the lenses of diabetics, the content of glucose correlated positively with that of adonitol, fructose, and sorbitol. In the lenses of nondiabetics, the content of glucose correlated positively with that of mannitol and inversely with that of 1-deoxyglucose and myo-inositol. In diabetics, hemoglobin A1 (%) correlated positively with the concentration of adonitol in the lenses and inversely with the concentration of lens myo-inositol; however, it did not correlate with the concentration of glucose in lenses. Regulation of both the metabolism of lenticular polyols and the pattern of polyols in serum may be necessary for normalizing lenticular polyol content.