BACKGROUND: Some Indonesian plants, such as Vaccinium varingiaefolium Miq., Plectranthus scutellarioides (L.) R.Br., Syzygium myrtifolium Walp., and Eclipta prostrata (L.) L., are rich of flavonoid and anthocyanin. Flavonoid, flavan-3-ol, quercetin, anthocyanin, and tannin compounds can reduce systemic vascular resistance because they cause vasodilation and are thought to be able to influence the function of angiotensin-converting enzyme (ACE) and inhibit ACE activity, which plays an important role in the process of hypertension. AIM: This study aims to determine the potential of some Indonesian plants to inhibit ACE activity. METHODS: Testing of ACE inhibitory activity is carried out by the hippuric acid compounds formed as a result of the reaction between the substrate and the enzyme, then measured spectrophotometrically. The inhibitory and IC50 values of each test sample were compared with the positive control of Captopril. RESULTS: The four plant extracts contained secondary metabolites, such as flavonoids, tannins, saponins, quinones, steroids, triterpenoids, and essential oils. Ethanol extract of V. varingiaefolium Miq., P. scutellarioides (L.) R.Br., S. myrtifolium Walp., and E. prostrata (L.) L. each had an IC50 value of ACE inhibition activity of 131.4 ppm, 206. 7 ppm, 151.2 ppm, and 196.0 ppm. The IC50 value of the Captopril with inhibition of ACE activity is 11.1 ppm. CONCLUSION: This study shows that some Indonesian plants have the activity to inhibit the ACE and potential antihypertensive drug candidates with ACE inhibitory activity.