ABSTRACTIntroductionPatients with Parkinson's disease (PD) may benefit from deep brain stimulation (DBS). Perifocal brain edema sometimes occurs after DBS surgery, but it is transient and does not affect the final prognosis. Transient deterioration of cognitive function has been reported in patients with frontal edema in the first postoperative week. This study aimed to investigate the effect of Goreisan in preventing edematous changes after DBS and determine the influence of edema on cognition.MethodsWe included 29 patients with PD who underwent bilateral subthalamic nucleus (STN) DBS and who were divided into 2 groups: those using (11 patients) and those not using Goreisan (18 patients). At 1 week postoperatively, all patients underwent magnetic resonance imaging. We measured the volume of edema either in the frontal white matter or STN on fluid‐attenuated inversion recovery (FLAIR) images. Finally, brain edema, motor function, and cognitive function were compared between the groups with and without Goreisan.ResultsIn the FLAIR image 1 week postoperatively, the average postoperative frontal subcortical edema (FE) volume of the group with Goreisan was significantly lower than that without Goreisan (2249 ± 2186 mm3, 6261 ± 7213 mm3, respectively, p = 0.023). Multivariate analysis with age, preoperative Mini‐Mental State Examination (MMSE) score, FE, and peri‐STN edema (SE) as factors, and MMSE at 1 week postoperatively as the dependent variable showed that preoperative MMSE score and SE were significant as associated factors.ConclusionsFE after DBS surgery may be alleviated using Goreisan. SE and preoperative MMSE scores were associated with MMSE scores 1 week postoperatively.Trial RegistrationNot applicable