In the field of work physiology, catecholamines and cortisol are used as strain indicators, because their production is increased in stressing work situations. Short-term stress cannot be ascertained by measuring catecholamines in urine. We studied the excretion of cortisol in saliva during short-term stress. We examined 77 healthy subjects who worked at a video display unit (VDU) for 30 min. They had to carry out a task with high speed and accuracy demands. Saliva specimens were taken before and after VDU work. Saliva cortisol levels were determined by means of a sensitive enzyme immunoassay (EIA). Additionally physiological parameters (heart rate, blood pressure, respiratory rate) and task performance were measured, and the subjects were asked about their feelings of stress and psychovegetative disorders. Saliva cortisol concentrations were significantly increased after 30 min of VDU work. Heart rate, blood pressure and respiratory rate were also increased during the task. In persons with high heart rate and blood pressure levels saliva cortisol increased significantly stronger during VDU work than in persons with lower heart rate and blood pressure levels. The results indicate that saliva cortisol is a useful strain indicator in short-term stress situations.