OBJECTIVE:To observe the correlation of concentration-time curves of riboflavin in salive and plasma.METHOD:After peple orally taking riboflavin tablets,the riboflavin in salive was determinated by fluorescence spectrophotometry with excitation wavelength 475.4nm and emission wavelength 524.7nm.RESULTS:The recovery of riboflavin was over 96%.The detection limits of riboflavin was 5ng.ml-1,and the calibration curve was linear in the range of 5ng.ml-1～3μg.ml-1.The regression equation was △F′=0.116c+0.232(r=0.9999).CONCLUSION:The concentration-time curves of riboflavin in salive was similar to these in plasma.