Nobiletin treatment ameliorated cardiac dysfunction in the DCM group, blunted the mRNA expression of NADPH oxidase isoforms p67phox, p22phox and p91phox, and abated oxidative stress, decreased the Tgfb1, Ctgf, fibronectin, and collagen Iα expressions and blunted cardiac fibrosis. This evidence concerns the gene CYBB and familial dilated cardiomyopathy.