The article investigates lipid peroxidation processes and the dynamics of the enzymatic antioxidant response of winter triticale under herbicidal stress, as well as the potential to mitigate oxidative stress through the combined application of natural origin. Field and laboratory research was conducted in 2023–2025 in the the Right Bank Forest Steppe of Ukraine. Dialen Super herbicide was applied at rates of 0.8; 1.0 and 1.2 l/ha both separately and in combination with plant growth regulator Kelpak (2.0 l/ha). The intensity of lipid peroxidation was assessed by the content of malondialdehyde, and the enzymatic antioxidant response was assessed by measuring the activity of catalase and peroxidase enzymes. On the 5th day, the content of malondialdehyde under the action of the herbicide exceeded the control by 64.7–111.0%, and the activity of catalase and peroxidase — by 40.3–77.6% and 40.5–81.0%, respectively. Addition of Kelpak reduced malondialdehyde content by 22.3–24.0% on the 5th day and by 20.2–29.9% on the 10th day compared to the corresponding herbicide treatments. On the 5th day, Kelpak additionally increased catalase activity by 16.9–18.0%, and peroxidase activity by 20.4–22.7%. On the 10th day, the effect of the plant growth regulator was accompanied by a consistently lower content of malondialdehyde and a decrease in peroxidase activity relative to the corresponding herbicide treatments, whereas the catalase response depended on the herbicide application rate. Taken together, these findings indicate an attenuation of the investigated component of herbicide-induced oxidative stress.