<p>Weeds negatively impact crop productivity, leading to the widespread use of synthetic herbicides for control. However, these substances adversely affect the environment and human health. Therefore, natural products are being explored as alternatives to synthetic herbicides due to their safer and more environmentally friendly nature. Phytochemicals, including dihydrochalcones like phloretin, have received attention for their biological effects. This study examined the phytotoxicity of phloretin (0─500&#xa0;μM) on hydroponically grown maize seedlings and identified its mode of action through various approaches, including proteomic analysis. Phloretin reduced root growth in a dose-dependent manner. This effect was accompanied by significant decreases in the KCN-sensitive respiration of root apexes and a decline in the ATP/ADP and ATP/AMP ratios of roots. In isolated mitochondria, phloretin inhibited state III respiration, suggesting that the primary mechanism underlying the respiration impairment is the inhibition of the F_oF₁-ATP synthase complex. In addition, under in vitro conditions, phloretin was able to oxidize NADH, suggesting that it could reduce its supply to the respiratory chain. Concurrently, shifts in respiratory patterns were accompanied by an upsurge in the activity of antioxidant metabolism enzymes and elevated levels of reactive oxygen species, malondialdehyde, and conjugated dienes. Proteomic analysis revealed that the impact of phloretin on seedling growth is intricately linked to changes in the abundance of proteins involved in defense mechanisms, energy production, and water transport functions. Overall, the observed attenuation of root growth, coupled with alterations in respiratory patterns, antioxidant metabolism, and protein abundance, suggests a multifaceted impact of phloretin on cellular processes.</p> Graphical Abstract <p></p>