Severe sepsis, especially septic shock, causes extensive ischemia–reperfusion (I/R) injury [42], which often occurs in the kidney, brain, gut, lung, myocardium, retina, etc. Quercetin has been found to alleviate I/R injury by activating Nrf2 through the MAPK and phosphoinositide 3-kinase (PI3K)/ protein kinase B (PKB, also known as AKT) signaling pathways [43]. The gene discussed is NFE2L2; the disease is Sepsis.