Taurine (2-aminoethanesulfonic acid) is a sulfur-containing amino acid widely distributed in mammalian tissues. Although taurine is structurally analogous to the neurotransmitter gammaaminobutyric acid, suggesting that it may promote neuroendocrine activity, its role in promoting psychological stress in human subjects remains unelucidated. To this end, we aimed to determine the impact of a single oral dose of taurine on psychological stress induced by a calculation task. Healthy adult male university students (n ＝ 20) participated in a double-blinded placebocontrolled crossover trial. On day 1 of the experiment, participants ingested 3 g of taurine or 1g of dextrin (placebo). After a 15-min rest period, each participant was challenged with two calculation tasks, each lasting for a period of 15 min and separated by a 5-min rest period. In the second part of the experiment, participants ingested 1 g of the dextrin placebo and were asked to remain seated, with no specific tasks provided (control). We collected saliva samples from each participant before and after the experimental trials. The levels of salivary amylase activity increased significantly in response to the dextrin ingestion in both the placebo (p＜0.01) and control (p＜0.05) settings but not in response to taurine ingestion. The concentration of salivary chromogranin A (CgA) decreased significantly in response to taurine ingestion (p ＜ 0.01) but not in response to the dextrin ingestion in both the placebo and the control experiments. The changes in amylase activity (placebo＞control＞taurine) suggested that the increase in amylase activity that was amplified by the calculation task was suppressed by taurine ingestion. Similarly, CgA concentration in saliva from participants in the control trial exhibited a decrease, but this was increased in response to the calculation tasks (placebo). Taurine ingestion not only suppressed this increase but also amplified its decrease. Collectively, our results indicated that taurine ingestion suppressed the increase in the amylase activity and the decrease in CgA concentration in saliva in response to a calculation task. This finding is consistent with previous reports indicating that taurine can activate inhibitory signals to suppress adrenergic stimuli.