Objectives: In this study, extracts from different parts of traditionally used medicinal plants were evalu-ated for their antioxidant activities in vitro. Methods: The free radical hunting or scavenging activity was measured by sample absorbance at 517 nm using spectrophotometer. Methanol and DPPH were used as a blank and negative control, respectively. Results: Medicinal plants showed high values of total phenolic (expressed as gallic acid equivalent, GAE) and flavonoid (expressed as quercetin equivalent, QE) contents of ethanolic extracts of Euphrasiae stricta (E. stricta, 58.19 GAE mu g/mg) and (42.44 QE mu g/mg), Euphorbia platyphyllos L. (E. platyphyllos L., 46.05 GAE mu g/mg) and (43.39 QE mu g/mg), Epimedium brevicomum Maxim. (E. brevicomum Maxim., 51.93 GAE mu g/ mg), and (39.21 QE mu g/mg), respectively. Plants have been found to be rich in phenolic and flavonoid compounds, and their hydroxyl groups are responsible for scavenging free radicals. Highest radical scav-enging activity was observed in the E. stricta (IC50 = 38.972 mu g/mL), E. platyphyllos L. (IC50 = 40.817 mu g/ mL), and E. brevicomum Maxim (IC50 = 46.265 mu g/mL), medicinal plants for both of their ethanolic and methanolic extracts as compared to the ascorbic acid scavenging activity (IC50 = 37.337 mu g/mL). Conclusions: It was found that the studied plants are capable of acting as important antioxidants that can be used to treat and inhibit extensive degenerative diseases caused by oxidative stress., including cancer, cardiovascular and inflammation diseases, atherosclerosis, dementia, diabetes, asthma, and eye degener-ative diseases. (c) 2023 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).