In order to study the biochemical abnormality of metabolites from tissues or cells at the molecular level, the surface enhanced Raman scattering technique was used to detect the serums from diabetes mellitus and complication (coronary disease, glaucoma and cerebral infarction). It is found that the characteristics surface-enhanced raman spectra (SERS) of serums are very similar to that from diabetes mellitus, which indicates that the changes of molecular structure or content from the metabolites of tissues or cells in these diseases are similar. The significant differences of SERS are found between normal and diseased serums. Especially, the relative intensity of the band from patients increases obviously at 725 cm-1.The partial reinforcement comes form the adenines’ contribution and is independent of the blood sugar level, which indicates that there exist many adenines in these serums. The results will offer the experimental basis for the biochemical study and clinical diagnosis of diabetes mellitus and complication.