Valerian (Valeriana officinalis L.) is a perennial flowering medicinal plant. Weed control in valerian is one of the main limiting factors for production of this species especially during the initial growth stage.Therefor, the aim of this study was to evaluate the effects of single and mixture applications of post-emergence graminicides and broad leaf herbicides on valerian plant . Three separated experiments were conducted in this study. In the first experiment, three rates (0.75X, X and 1. 25X that X is equal to the recommended dosage ) of haloxyfop-R- methyl ester , sethoxydim, oxadiargyl, bentazon, oxadiazon, and oxyfluorfen were applied at 3-4 leaf stages to valerian plant to select herbicide type and rate for post controlling broadleaf and grass weeds in this species. In the second experiment, two broad leaf herbicides (oxadiazon and oxadiargyl, in two doses: 0.75X and X) and two graminicide herbicides (haloxyfop-R- methyl ester and sethoxydim, in recommended dose) which selected base on the first experiment, were evaluated alone and in mixture. In the third experiment, the oxidative stress that was made by herbicides application such as oxyfluorfen and bentazon, which in the first experiment caused the most herbicide injury in six doses including 0.25X, 0.50X, 0.75X, 1X, 1.25X and 1.5X, was evaluated. All of the experiments were base on randomize complete block designed in factorial arrangement with three replications. Oxyfluorfen application caused the most herbicide injury followed by bentazon and the injury increased as the rate and date of application increase, and whereas SPAD, leaf number, shoot diameter, shoot dry weight as decreased the rate of application increased. Oxadiazon only caused significant damages at 30 days after application under all three rates. while other treatments showed no marked injuries under any rate or date after application as compared with the control. As a whole, the results of first experiment showed that oxadiargyl under all three rates, oxadiazon , at recommended dose and % 25less than recommended dose, haloxyfop-R and sethoxydim under all three rates may be used safely for weed control in valerian plants. The results of second experiment showed that mixture of oxadiazon and sethoxydim at two recommended doses and %25 less than recommended dose caused no marked injuries, and had the highest increase in SPAD, plant height, leaf number, shoot diameter, shoo dry weight, root dry weight, performance and percentage of essential oil. Also, the results of second experiment showed that mixture of oxadiargyl and haloxyfop-R-methyl ester caused the most damage and highest reduction in all of measured characteristics as compared with the control. In the third experiment, the level of CAT and APX enzymes activite increased under oxyfluorfen and bentazon herbicide application as compared with control, however such increases were not able to prevent plant injury. The overall resultes showed that haloxyfop-R- methyl ester , sethoxydim, oxadiargyl, oxadiazon and mixture of oxadizaon and sethoxydim may be used to control weeds in valerian. Keywords : Valerian, Selective weed control, Mixed of herbicides, Oxidative stress.