Mental stress, such as anxiety and conflict, causes physiological changes, such as changes in autonomic nervous activity and gastric ulcers. In addition, stress induces glucocorticoids and changes the hippocampal brain-derived neurotrophic factor (BDNF) expression levels. We previously reported that Acanthopanax senticosus HARM (ASH) prevents stress-induced gastric ulcers. Thus, we investigated the potential anxiolytic effect and influence of ASH on the hippocampus BDNF-related protein in male Sprague-Dawley rats fed 1% and 5% ASH extract-containing food for one week using novelty suppressed feeding (NSF) and improved elevated beam walking (IEBW) tests. ASH treatment significantly decreased latency to eat in the NSF test and increased the time spent on the open arm in the IEBW test. ASH5% treatment showed a significant decrease in LFnu, indicative of sympathetic nervous activity, and a significant increase in HFnu, indicative of parasympathetic nervous activity, in the NSF test. In addition, ASH1% and ASH5% treatments significantly decreased LFnu and significantly increased HFnu in the IEBW test. ASH5% treatment significantly increased hippocampal BDNF protein expression in both Western blotting and immunohistochemistry experiments. Our findings suggest that anxiolytic effects of ASH occur via the regulation of autonomic function and increased hippocampal BDNF signaling.