['Activation of hepatic stellate cells (HSCs) is a hallmark of liver fibrosis. Quercetin has benefits for liver fibrosis, but the mechanisms are unknown.', 'We investigated the quercetin effect on HSC survival and the role of endoplasmic reticulum stress (ERS).', 'Rat HSCs and LO2 hepatocytes were treated with quercetin (0.5-120\u2009μM) for 24\u2009h. Quercetin (10-40\u2009μM) effects on apoptosis for 24\u2009h were analyzed by flow cytometry and TUNEL staining. Quercetin (10-40\u2009μM) effects on the expression of Bcl-2, caspase-9, caspase-3, PARP-1, PERK, IRE1, ATF6, calnexin and CHOP for 24\u2009h were analyzed by Western blot. Quercetin (10-40\u2009μM) effects on mRNA expression of calnexin and CHOP for 24\u2009h were analyzed by Real-time PCR.', 'Quercetin at concentrations greater than 20\u2009μM significantly inhibited HSC proliferation (IC'] Does quercetin stimulate mitochondrial apoptosis dependent on activation of endoplasmic reticulum stress in hepatic stellate cells?