Objective:To investigate the antioxidant and the antibacterial activities of crude extract from aerial part of Polygonum maritimumL.(Polygonaceae)(P.maritimum)and to find new actives biomolecules.Methods:The whole plant was collected from the Rechgoune coast(West of Algeria),and methanolic crude extract of aerial parts ofP.maritimum(PMCE)was prepared.The extract was tested against different bacterial strain and tested for his ability to neutralize free radical(DPPH)and to scavenge the H2O2.Results:PMCE had a very high content of total phenol,which was(352.49依18.03)mg/g dry weight,expressed as gallic acid equivalent.PMCE exhibited excellent antioxidant activity,as measured using DPPH and H2O2 scavenging assays.It also showed a high antibacterial activity against gram-positive bacterial strains:Bacillus cereus,Bacillus subtilisandStaphylococcus aureus with an highest MIC of 120μg/mL.Conclusions:The antioxidant and antibacterial activity of the PMCE is probably due to phenolic compounds present in the extract.The contemporary presence of antioxidant and antibacterialactivities in the PMCE suggests that this plant may be a source of bioactive substances with multifaceted activity. Objective: To investigate the antioxidant and the antibacterial activities of crude extract from aerial part of Polygonum maritimum L. (Polygonaceae) (P. maritimum) and to find new actives biomolecules. Methods: The whole plant was collected from the Rechgoune coast (West of Algeria ), and methanolic crude extract of aerial parts of P. maritimum (PMCE) was prepared. The extract was tested against different bacterial strain and tested for his ability to neutralize free radical (DPPH) and to scavenge the H2O2. Results: PMCE had a very high content of total phenol, which was (352.49 according to 18.03) mg / g dry weight, expressed as gallic acid equivalent. PMCE exhibited excellent antioxidant activity, as measured using DPPH and H2O2 scavenging assays. Also also showed a high antibacterial activity against gram- positive bacterial strains: Bacillus cereus, Bacillus subtilis andStaphylococcus aureus with the highest MIC of 120 μg / mL. Conclusions: The antioxidant and antibacterial activity of the PMCEs probably due due to phenolic compound s present in the extract. contemporary presence of antioxidant and antibacterialactivities in the PMCE suggests that this plant may be a source of bioactive substances with multifaceted activity.