Four hundred and fifty two male angina patients were randomised to rec
eive stress management or no psychological intervention. Instruction i
n stress management was given in three group sessions each of about on
e hour. Patients were also asked to practice relaxation and read a cou
rse 'manual' at home. After six months the group instructed in stress
management showed a reduction in the frequency of non-exertional chest
pain (as measured by a 14 day diary) compared to the non-intervention
group. Analysis of covariance showed a benefit of stress management i
rrespective of angina frequency at recruitment. Further analysis of co
variance showed reduction in the frequency of non-exertional chest pai
n to be associated with increased ability to relax. This study has dem
onstrated that stress management can be effective in reducing the freq
uency on non-exertional chest pain, and that a possible mechanism for
this lies in the practice of relaxation.