This paper evaluates the effects of the short- (1 g/kg) and long-term (0.5 and 1 g/kg/day) oral intake of egg white hydrolysed with pepsin (hEW) and the long-term oral intake (1 g/kg/day) of egg white (EW) on local angiotensin-converting enzyme (ACE) activities in plasma and other tissues of spontaneously hypertensive rats (SHR), as compared to the effect of the ACE inhibitor prototype captopril. The rats treated with hEW were classed in a different group than the control rats and the rats treated with EW by cluster analysis, taking into account their tissue ACE activities and their systolic blood pressure (SBP). Principal component analysis (PCA) showed that SBP in SHR was negatively related with ACE activity in plasma and positively related with ACE activity in aorta and kidney. ACE activity in plasma significantly increased after the long-term treatment with hEW (0.5 g/kg/day). ACE activity in aorta and kidney was significantly inhibited 4 h after the short-term administration of hEW. The long-term treatment with hEW caused local effects on ACE activity in aorta, kidney and lungs that followed a pattern similar, but less pronounced, than that caused by captopril.