A new excitation-emission spectrofluorimeter with optical fiber light delivery and collection for use in rapid analysis of tissues in a clinicaI setting is presented. This system provides ten different excitation wavelengths, permitting collection of spectra from biological tissues in approximately. 600 ms. Fluorescence spectra were acquired in 10 patients who undergo routine endoscopic procedures for gastrointestinal disorders. Normal and adenomatous mucosa were studied with optical fiber contact probe throught the endoscope. We found that adenomas exhibit increased hemoglobin absorption compared to normal mucosa; adenoma fluorescence is less intense compared to normal tissue; and increased red fluorescence is observed in polyps. Conclusions: The multiexcitation provides information about optimal excitation wavelengths for the differentiation of normal and neoplasic colon and also the identity ofthe fluorophores which contribute to total tissue fluorescence.