The main goal of this study was to determine the phenol content, the antibacterial and the antioxidant activities of the three species of Lannea largely use in traditional medicine in Burkina Faso. The total phenolic and flavonoid contents of hydro alcoholic extract (70%V/V ethanol/distilled water) from the barks of Lannea acida, Lannea microcarpa and Lannea velutina (Anacardiaceae) were determined by the method of Folin Ciocalteu and AlCl3 by spectrophotometry. These extracts were tested for their antioxidant and antibacterial activities. Antioxidant activity was determined by the method of DPPH and compared with quercetin. Antibacterial activity was performed by disk diffusion and broth microdilution essays against nine reference bacterial strains including gram-positive and gram-negative bacteria. L.acida exhibited the highest total phenolic contents (40.55±0.26 g GAE/100 g) which correlated with better antioxidant activity (IC50 = 345.72±7.76 ?g mL-1). Furthermore the highest content of total flavonoids (11.02±0.04 g QE/100 g) and the largest anti bacterial spectrum (7.82 ?g mL-1?MIC? 62.5 ?g mL-1) were recorded with L.velutina. These results show that the barks of L. acida and L.velutina could be used respectively as a potential natural antioxidant and antibacterial agent.