The aim of the present study was to investigate the effects of a group structured intervention on the mental and physical discomfort and immune function of 20 family caregivers. A structured intervention for caregivers consists of five sessions, each of which lasts 90 min. This was a modified version of the program that had been originally developed for cancer patients. All the family caregivers were female and ranged in age from 47 to 66 years (mean: 54.7 +/- 4.4). The period of care at home ranged from 1 to 12 years (mean: 5.8 +/- 2.7). Concerning the original diseases of the care-receivers, 10 had vascular dementia and eight had Alzheimer's disease. Nine out of 20 caregivers had no care support, and seven utilized no public resources such as day-care centers. Only five caregivers felt that they were healthy. Two psychometries, that is, Profile of Mood States (POMS) and General Health Questionnaire-30 (GHQ-30) were administered and blood samples were drawn before and after intervention. Comparison of results showed that there was significant improvement (P < 0.05) in the scores of depression, anger-hostility, fatigue and confusion in the POMS, and physical symptoms, anxiety-mood disorder, suicidality-depression in the GHQ-30. Also, there was significant (P = 0.0325) augmentation of natural-killer cell activity. The present study suggests that this kind of intervention was effective for relieving emotional and physical discomfort, and also for improving immune function.