Methanolic and aqueous extracts of nine Algerian plant species used in folk medicine were investigated for their antimicrobial activities against five bacteria strains: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterobacter aerogenes and one fungus: Candida albicans . The plants exhibited important antimicrobial activity with a significant difference between the different plants. The most active plants were Tamarix gallica, Rhetinolepis sp and Muscari Comosun. Most of the tested plant extracts were active against Candida albicans. Of all extracts, the Methanolic extract of Rhetinolepis sp was the most active (diameter ranges between 15mm and 22mm) whereas, the aqueous extract of Tamarix Gallica was the most active of all tested aqueous extracts (Diameter ranges between 10 mm and 17 mm).