The objective of this study was to contribute to a better knowledge of the medicinal flora by evaluating the antioxidant potential of extracts of five medicinal plants acclimatized in Burkina Faso. A phytochemical screening was performed by using the tests tube and thin chromatography methods. The content of phenolic compounds was evaluated by techniques using the Folin ciocalteu reagent. The antioxidant activity of extracts was assessed using 2, 2-azinobis-3-ethylbenzothiaz oline-6-sulfonic acid (ABTS), Ferric Reducing Antioxidant Power (FRAP) and 2-2-Diphenyl-1-Picrylhydrazyl (DPPH) methods. The results showed that chemical compounds such as tannins, flavonoids and saponosides were present in most methanolic extracts. The determination of phenolic compounds showed that the methanol extract of E. camaldulensis contains the highest content (68.62 mg EAG/g extract). The antioxidant activity of the studied plants varies from one extract to another depending on the method used. The methanol extract of H. suaveolens showed the highest antioxidant content using the FRAP method (54.41 TEQ/g extract), while the methanol extract of E. camaldulensis recorded the highest antioxidant contents by ABTS and DPPH methods (28.99 ± 0.17 and 30.74 mg TE/g extract respectively). In addition, the methanol extract of E. camaldulensis exhibited very high antioxidant activity with an antioxidant activity index of 45.97. These plants are potential sources of natural antioxidant. In perspectives, the compounds responsible for the antioxidant activity will be isolated and their structure elucidated.