The present invention relates to multimodal spectroscopy (MMS) as a clinical tool for the in vivo diagnosis of disease in humans. The MMS technology combines Raman and fluorescence spectroscopy. A preferred embodiment involves diagnosis cancer of the breast and of vulnerable atherosclerotic plaque, esophageal, colon, cervical and bladder cancer. MMS is used to provide a more comprehensive picture of the metabolic, biochemical and morphological state of a tissue than afforded by either Raman or fluorescence and reflectance spectroscopies alone.