Objective:To evaluate the effect of Mongolian medicine Eerdun Wurile on postoperative cognitive function in elderly patients undergoing thoracoscopic lobectomy.Methods:Sixty elderly patients of either gender, aged ≥60 yr, of American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ, with body mass index≤28 kg/m 2, with preoperative Mini-Mental State Examination (MMSE) score ≥27 points, undergoing thoracoscopic lobectomy under general anesthesia, were divided into 2 groups ( n=30 each) using the random number table method: control group (group C) and Eerdun Wurile group (group E). Eerdun Wurile 15 capsules per day were taken for 7 consecutive days starting from 3 days before surgery in group E, and placebo was given instead in group C. The peripheral venous blood samples were collected before medication at 3 days before surgery (T 1) and 24 and 72 h after surgery (T 2, 3) for determination of the concentrations of serum brain-derived neurotrophic factor (BDNF), interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α) and Tau proteins by enzyme-linked immunosorbent assay. The patients′ cognitive function was assessed by MMSE at T 1 and 5 days after surgery (T 4), and the occurrence of cognitive decline (MMSE score < 27) was recorded. Results:Compared with group C, the serum BDNF concentration was significantly increased at T 2 and T 3, and the concentrations of IL-1β, TNF-α and Tau protein were decreased, the MMSE score was increased at T 4, and the incidence of cognitive decline was decreased in group E ( P<0.05). Conclusions:Mongolian medicine Eerdun Wurile can improve postoperative cognitive function in elderly patients undergoing thoracoscopic surgery, and the mechanism may be related to reduction of systemic inflammatory responses and promotion of nerve cell repair and regeneration.