This study evaluated the efficacy of the undergraduate service program "Controlling Stress & Tension" at the University of Maryland in terms of improving the health status of participants across biomedical stress reactivity and psychometric variables. Six hundred fifty-three participants were compared to 264 control subjects for pre- to post-program changes across the four psychophysiological stress response variables of frontalis EMG, pulse rate, pulse amplitude, and skin potential response as well as three psychometric variables including Type A/B behavior, locus of control, and manifest anxiety. Post-test analysis revealed that program participants displayed significantly lower measured stress activity for frontalis muscle tension, pulse amplitude, and skin potential response compared to control subjects. Psychometric changes included significantly reduced manifest anxiety and a significant locus of control shift to internality in program participants compared to controls. The results indicate that, in relation to several measures of biological integrity and mental well-being, the program under investigation was producing a significant, beneficial impact on human health via the precursors to psychosomatic disease. (Author/JD)