Objective To track the catabolic route and clearance of ena-lapril maleate tablets in vivo by surface -enhanced Raman scattering spectrometry , and put forward proposal to its safe medication.Methods The urine and feces of 15 patient exemplars was collected , pre-processed , blended with an equal volume of surface -enhancer , and tested at the identified peak of enalapril maleate of (1470 ±2 ) /cm.Then the clearance of active pharmaceutical ingredient was calculated and analyzed .Results The methodical recovery was high and the relevant standard deviation was within 3%.The active pharmaceutical ingredient was in good linear at the concentration of 5~100μg· mL-1 in urine and in feces, and the limit of detection was 0.5 μg · mL-1 and 1.3μg· mL-1 , respectively.Enalapril was effective to 11 exemplars, while its clinical effect was not responded on 4 exemplars.Conclusion The method is proved to be prompt and rapid , appropriate to the catabolic analysis in vivo and clinical evaluation to angiotensin -converting -enzyme Ⅰinhibitors.