Because of the above-mentioned effects of Cinnamomum, also due to the fact that cinnamon is widely used as an additive and since its underling mechanisms in depression have not been experimentally investigated, this study was designed to assess the effect of HEC on the BDNF protein and its receptor gene expression (TrkB) in prefrontal cortex of depressed rats. The gene discussed is NTRK2; the disease is depressive symptom measurement.