Due to having a short half-life and novel site of action, the herbicidal potential of natural compound are lionized.Coumarin is a secondary metabolitefrom Lavandula sp., family Lamiacae. Theimpact of eight concentrations of coumarin (0, 100, 200,400, 800, 1600, 3200 and 6400 ppm) were separately used as a pre-plant incorporated into soil on six plant species under greenhouse conditions. Generally, coumarin had phytotoxic effect against all plant species. The phytotoxic effect was concentration-dependent. The high concentrations could inhibit the emergence of seedlings (probably germination of seeds). Based on ED50 parameter, the ranking of plant species for tolerance to coumarin wasS. halepnse>Z. mays>C. album>A. retroflexus>E. cruss-gali>P. oleracea.Based on selectivity index, coumarin at a concentration of 365.69 ppm can control P. oleraceawithout damaging to Z. mays, whereas it at any concentration con not control other weeds without damaging to Z. mays.

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