Background: Understanding what causes changes in the flux of free fatty acids (FFA) is important to elucidate the etiology of metabolic syndrome. The first aim of this study was to test whether or not hormones and the autonomic nervous system influence blood FFA levels. A secondary aim was to test by means of a multiple group path analysis whether the consumption of fermented red ginseng (FRG; Panax ginseng) would influence those causal relationships. Methods: Ninety-three postmenopausal women (age 50e73 yr) were randomly divided into two groups. One group (44 women; age, $58.4{pm}5.9yr$; body mass index, $3.6{pm}2.5kg/m^2$) was supplied place capsules and the other group (49 women, age $58.4{pm}5.5yr$; body mass index, $22.9{pm}2.4kg/m^2$) was supplied FRG capsules. Both prior to and after the study (2 wk), blood samples were collected from the participants and several blood variables were measured and analyzed. Results: Squared multiple correlations of FFA were 0.699 in the placebo group and 0.707 in the FRG group. The unstandardized estimate of estradiol (E2) for FFA was 0.824 in both groups. Conclusion: The path coefficients of cortisol and the branchial pulse for FFA were significantly different between the FRG group and the placebo group.