PHYSICOCHEMICAL characterization of arena 7% OD herbicide formulation and spray tank solutions, as well as its phytotoxic effects, were studied to investigate the problems caused by its application to manage weeds on common wheat plants. Cultivators recorded that application of the herbicide in 2020 destroyed about 20% of common wheat in some governorates in Egypt. A ready-made sample of the herbicide was used in the study. Three different concentrations of the herbicide were applied which include half recommended, recommended and double recommended doses. Phytotoxic action on the common wheat plant was studied under laboratory and outdoor conditions. Morphological parameters measured under laboratory conditions are relative root length (%), relative shoot length (%) and relative germination ratio (%). Phytotoxic parameters measured in outdoor experiments include biomass (g), plant length (cm), spike weight (g), grain weight (g), stem and root lengths (cm) and weights (g). The results obtained revealed that both pesticide formulation and its spray solutions pass successfully the required tests according to the standard organizations. Arena 7% OD has phytotoxic effects on seed germination (%) and seedling growth especially the double recommended dose. The outdoor experiment indicated that the tested herbicide is non phytotoxic to wheat. Both half and full recommended (600 ml.ha-1 and 1200 ml.ha-1) doses non–significantly increased the common wheat yield components as plant length and plant biomass. Based on the obtained data, it turns out that away from the quality of arena formulation there are other factors caused its undesirable effects on common wheat in Egypt.