Mouthwashes provide an important means for improving oral hygiene. This study investigated the psychophysiological effects of mouthwashes with different binders during the recovery after a short-term stressor. In a within-subject experimental design, 21 healthy adults used four mouthwashes; MW A (no binder), MW B (Sodium alginate 0.16%), MW C (Sodium alginate 0.32%), and MW D (Xanthan gum 0.08%), after a 20-minute calculation task. Subjective evaluations and physiological responses including skin conductance level and electrocardiogram were recorded throughout the experiment. MW C exhibited an increased high-frequency (HF) component of heart rate variability (HRV) during recovery, and a significant difference in “strength of thickness” compared to other mouthwashes. MW D showed a greater decrease in heart rate and increased HF component of HRV compared to MW B. The findings suggest that mouthwashes with higher thickness levels effectively promote recovery from the physiological stress response, and are potentially suitable for relaxation purposes.