The aim of the present study was to investigate the mechanism underlying the rescue effect of lipid emulsion on bupivacaine (BPV)‑induced cardiomyocyte toxicity. The inhibitory effects of BPV on H9c2 myoblast cell proliferation were investigated using an MTT assay. The H9c2 myoblast cells were treated with either 1 mM BPV or 1% lipid emulsion (LE) alone, or co‑treated with both of the drugs. Cell apoptosis was detected using both Annexin V/propidium iodide staining and a terminal deoxynucleotidyl transferase dUTP assay. The protein expression levels of apoptosis-associated proteins were quantified using western blot analysis, and the mRNA expression levels were quantified by reverse transcription‑quantitative polymerase chain reaction. The expression levels of reactive oxidative species, malondialdehyde, superoxide dismutase, and catalase were quantified using the optical density values obtained from a spectrophotometer. In addition, the mechanism underlying the mitochondrial function of the H9c2 myoblast cells was investigated using both JC‑1 staining, and cyclosporin A and atractyloside treatment. The results indicated that the H9c2 myoblast cells treated with BPV exhibited significantly higher levels of apoptosis. Furthermore, BPV treatment increased the levels of oxidative stress, and caused mitochondrial dysfunction within the H9c2 myoblast cells. LE treatment reversed the effects of BPV treatment in the H9c2 myoblast cells.