The aims of this experiment were to determine the effect of Potassium, Magnesium, Copper, Sodium, Lithium, Barium, and Calcium ions on the growth rate and enzymatic activity of Peroxidase in Zea mays roots and coleoptiles using pyrogallol and 24 well spectrophotometer. We deduced that overall excess metal ions used in this experiment did have a detrimental effect on the growth rate of Zea mays seedlings due to an increase in the production ROS (Reactive Oxygen Species) due to which the plant was increasing the activity of Peroxidase enzyme. We concluded that Zea mays that had lower growth rates, and subsequently higher enzyme activity were in fact because the majority of the damages to roots and shoots were done by the ROS for which the plants were increasing the Peroxidase enzyme activity. Moreover, we also concluded that as the growth rate decreased, the Peroxidase enzyme activity was increased in seedlings treated with excess metal ions, suggesting that ROS might be one of the significant factors in causing damage to the plant's roots and shoots and hindering their growth.