['\u2002 The human hepatocellular carcinoma (HCC) cell line HepG2 can easily acquire resistance to doxorubicin. However, the mechanism of action is unclear.', '\u2002 In the present study, we used confocal microscopy, flow cytometry and other methods to reveal the mechanisms by which HepG2 cells acquire doxorubicin resistance.', '\u2002 Our results showed that R-HepG2 cells, a doxorubicin-resistant sub-line of HepG2, exhibited decreased intracellular accumulation of doxorubicin and increased expression of P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 when compared with HepG2 cells. R-HepG2 cells also harbored higher levels of glutathione and increased expression of glutathione peroxidase. Furthermore, we demonstrated that the phosphorylation of mitogen-activated protein kinases (p38 and c-jun-N-terminal kinases), IkBα and CREB were increased in R-HepG2 cells. Specific p38 inhibitor SB203580 decreased P-gp expression. The multi-kinase inhibitor sorafenib tosylate also significantly suppressed the phosphorylation of these proteins and inhibited the expression of P-gp.'] Are increased glutathione and mitogen-activated protein kinase phosphorylation involved in the induction of doxorubicin resistance in hepatocellular carcinoma cells?