Abstract: To the present study aimed to investigate the protective effects of Erlong Zuoci Pills on oxidative stress induced by hydrogen peroxide (H₂O₂) in House Ear Institute-Organ of Corti 1 (HEI-OC1) and to explore the mechanism by cellular metabolomics. There were 6 groups in the experiment: the control group, model group, three dose groups of ELZC (low, medium, and high), and positive control ascorbic acid group. The oxidative stress injury model was established in the HEI-OC1 by inducing 0.9 mmol/L H₂O₂ for 12 h. The proliferation of HEI-OC1 cells was observed by CCK-8 assay; the contents and activity of lactate hydrogenase (LDH), reactive oxygen species (ROS), and superoxide dismutase (SOD) in HEI-OC1 cells were detected by corresponding kits. Finally, the endogenous substances of cells were analyzed from the perspective of metabolomics. Compared with the model group, ELZC groups could significantly increase the cell proliferation rate after administration. Moreover, they could also ameliorate the increase of ROS and LDH content and the decrease of antioxidant enzyme SOD caused by H₂O₂. Metabolomic results revealed significant differences among multiple groups in the scores of partial least squares discriminant analysis. The ELZC group could relocate the model group back to the control group. The metabolic regulation of ELZC on oxidative stress in HEI-OC1 cells mainly affects nucleotide metabolism and amino acid metabolism. In summary, the results indicate that ELZC exhibits protective effects on H₂O₂-induced oxidative stress in HEI-OC1 cells. Additionally, this protective effect may be produced by increasing the content of amino acids such as uridine and phenylalanine, thereby regulating pathways such as pyrimidine metabolism, phenylalanine metabolism, biosynthesis of phenylalanine, tyrosine, and tryptophan, and histidine metabolism.