Wuzi Yanzong prescription inhibited the UPR and ER-stress-induced apoptosis, possibly leading to an improvement in both PD symptoms and lesions. Specifically, the GRP78, p-PERK, p-eIF2α, ATF4, p-IRE1α, XBP1, ATF6, and CHOP ER related proteins were decreased after pretreatment in PD mice. The gene discussed is XBP1; the disease is Parkinson disease.