Objective To study the role of polyamines (putrescine, spermidine and spermine) in regulating ornithine decarboxylase (ODC) protein levels in the early regenerating liver of rats. Methods Exogenous polyamines (dissolved in 0.9% NaCl) were administered subcutaneously to adult male SD rats (180～220g). The ODC protein levels in the regenerating liver induced by partial hepatectomy (PH) were measured by Western blotting analysis. Results The treatment with high doses of putrescine ( 20 mg/kg body weight), spermidine (0.15 mg/kg body weight) or spermine ( 6 mg/kg body weight) reduced the ODC protein level compared with the control group within 12 hours after PH. However,the treatment with low doses of putrescine (0.02 mg/kg), spermidine (0.03 mg/kg) or spermine (0.06 mg/kg) resulted in a rapid increase in the protein level in the 4th hour after PH, which was 15.1%, 29.5% or 30.3% higher than that of control rats respectively.Conclusion Polyamines with certain doses play a role in the feedback regulation of ODC protein levels in the early regenerating liver, where spermidine and spermine play a greater role than putrescine dose.