Purpose: Smoking is a way of coping with anxiety and stress. This study aimed to identify the effects of forest-thermal combined therapy on anxiety and depression in smokers who desire to quit smoking. Methods: Thirty participants were included in the study, 15 in the experimental group and 15 in the control group. Those in the experimental group participated in a three-day forest-thermal combined therapy program. The program includes forest walks, meditation and thermal therapy in the charcoal kiln. Results: Before and after the program, physiological indicators such as cortisol, heart rate variability, and serotonin anxiety level using the state-trait anxiety inventory (STAI), and stress level using the psychosocial well-being index (PWI) were measured in both groups. The differences in STAI (p=.012) and PWI (p=.006) scores between the experimental and control groups were statistically significant. However, cortisol, heart rate variability, and serotonin were not significantly different between the two groups after the program. Conclusion: These results show that forest-thermal combination therapy effectively reduces anxiety and stress in smokers. It suggests that forest-thermal therapy can potentially increase smoking cessation rates.