The purpose of this study was to investigate tetrahydropalmatine (THP), a major compound in Corydalis yanhusuo WT Wang (Family: Papaveraceae) and its effects on PTSD induced neurobehavior in the rodent model. The aims were to determine the effects of THP on anxiety, locomotion, and memory. A prospective experimental between groups design was used. Eighty rats were randomly divided into two groups, non-stressed and stressed. They were then randomly subdivided into four groups: control, THP, midazolam, or THP and midazolam. The behavioral component was evaluated using the elevated plus maze (EPM) and Morris water maze (MWM) in a restraint/shock stress model. Data analysis was performed using a two-tailed Multivariate Analysis of Variance (MANOVA) and LSD post-hoc test. There were significant differences in anxiety between the groups (P<0.05). The PTSD stressed rat groups had significantly reduced time on the open arms of the EPM demonstrating significant increased anxiety compared to the control nonstressed groups. Data pertaining to the MWM did not demonstrate statistical significance. While a one-time dose of THP was insufficient in providing a significant decrease in anxiety, a multi-dose regimen may yield more effective results. Future experiments should evaluate a multi-dose or prophylactic regimen.