Forest bathing trip is a short, leisurely visit to forest. In this study we determined the health effects of forest bathing trip on elderly patients with chronic obstructive pulmonary disease (COPD). The patients were randomly divided into two groups. One group was sent to forest, and the other was sent to an urban area as control. Flow cytometry, ELISA, and profile of mood states (POMS) evaluation were performed. In the forest group, we found a significant decrease of perforin and granzyme B expressions, accompanied by decreased levels of pro-inflammatory cytokines and stress hormones. Meanwhile, the scores in the negative subscales of POMS decreased after forest bathing trip. These results indicate that forest bathing trip has health effect on elderly COPD patients by reducing inflammation and stress level.