Tai Chi, a moving meditation, is examined for its efficacy in post-stressor recovery. Forty-eight male and 48 female Tai Chi practitioners were randomly assigned to four treatment groups: Tai Chi, brisk walking, mediation and neutral reading. Mental arithmetic and other difficult tests were chosen as mental challenges, and a stressful film was used to produce emotional disturbance. Tai Chi and the other treatments were applied after these stressors. After all treatments, the salivary cortisol level dropped significantly, and the mood states were also improved. In general the stress-reduction effect of Tai Chi characterized moderate physical exercise. Heart rate, blood pressure, and urinary catecholamine changes for Tai Chi were found to be similar to those for walking at a speed of 6 km/hr. Although Tai Chi appeared to be superior to neutral reading in the reduction of state anxiety and the enhancement of vigour, this effect could be partially accounted for by the subjects' high expectations about gains from Tai Chi. Approaches controlling for expectancy level are recommended for further assessment.