To prevent hypertension, which can cause various diseases, it is important to improve lifestyle habits such as eating habits. Bananas are rich in GABA, which has been reported to have hypotensive and stress-relieving effects. To evaluate the effects of long-term banana intake on blood pressure, defecation, and mental state, a randomized, parallel-group clinical trial was conducted. 78 Japanese with high blood pressure took either of the two bananas with different GABA contents for 4 weeks or did not take bananas. As a result, systolic blood pressure was significantly lower in both banana intake groups after ingestion compared with before ingestion. In addition, the number of bowel movements, the number of days of bowel movements, and the amount of bowel movements significantly increased. Significant improvements in the subjective questionnaires "fatigue" and "tension" were also observed. These results suggest that banana intake may have the effect of lowering blood pressure, promoting defecation, and improving mental state.