We evaluated the influence of an acute inflammatory reaction that triggers the synthesis of exportable proteins by hepatocytes on liver regeneration after partial hepatectomy, which induces the synthesis of proteins necessary for liver cell proliferation. In hepatectomized rats with a turpentine-induced acute inflammatory reaction, the first peaks of hepatic DNA synthesis and mitosis were significantly inhibited compared with pair-fed controls subjected to partial hepatectomy only, and the liver DNA concentration at various times after partial hepatectomy was significantly lower in the former than in the latter. Inhibition was not obtained when the acute inflammatory reaction was induced 12 h or more before partial hepatectomy, suggesting that the inhibitory effect of turpentine administration depended on early events in the acute inflammatory reaction. These data suggest that one possible mechanism responsible for inhibition of regeneration might be competition at the transcriptional or the translational level between liver syntheses of various proteins, and that, under certain conditions, liver-specific functions might take precedence over regenerative functions.