Brain-body communication is pivotal in depression, encompassing intricate interactions among the nervous system, endocrine system, and immune system. Growing evidence suggest that the gut-brain axis is significantly involved in depression. Notably, fecal microbiota transplantation (FMT) from depressed patients or rodents with depression-like behaviors can induce depression-like behaviors in recipient rodents. Importantly, subdiaphragmatic vagotomy prevents these depression-like behaviors as well as antidepressant effects of serotonergic drugs. Furthermore, the novel antidepressant arketamine appears to restore the disrupted gut microbiota in rodents with depression-like behaviors, contributing to its therapeutic effects. There is increasing evidence of the vagus nerve’s role in the gut-brain axis. This chapter reviews the role of the gut-brain axis via the vagus nerve in depression and discusses the potential of FMT and transcutaneous auricular vagus nerve stimulation as therapeutic options for depression.