We investigated dehydroepiandrosterone (DHEA) secretion in response to acute psychosocial stress and the relations of DHEA secretion to cortisol secretion, cardiovascular activity, and negative mood changes. Thirty-three male students (mean age 22.6 years) were subjected to the psychosocial stress test "Trier Social Stress Test" (TSST), in which the participants were asked to deliver a speech and perform a mental arithmetic task in front of two audiences. Collections of saliva, measurements of blood pressure and heart rate, and assessments of negative mood by visual analog scales were conducted before, during, and after TSST. Acute psychosocial stress significantly increased salivary DHEA level by an average of 60% immediately after TSST. The peak of DHEA concentration preceded that of cortisol concentration by about 10 min. DHEA response was moderately correlated to cortisol response (r=.34, r(s)=.49) but not to cardiovascular response. Lower DHEA level and elevated cortisol/DHEA ratio during TSST were significantly and moderately correlated with increased negative mood during and after TSST. These results indicated that an acute increase in DHEA concentration under stressful situations might be partly mediated by the activity of hypothalamus-pituitary-adrenal axis and could have some significance in the improvement of negative mood.