The levels of plasma cortisol, blood glucose, serum triglycerides (TG) and total cholesterol (TC) were estimated in 175 human subjects (50 normal controls, 65 having essential hypertension and 60 suffering from rheumatoid arthritis. The results showed a significant elevation in the levels of plasma cortisol and blood glucose in both the stressed clinical groups with respect to controls. Increased levels of atherogenic lipids (TG and TC) were also observed in diseased group. However, in rheumatoid arthritis the biochemical changes were comparatively more pronounced than in hypertensives. The findings in vitro reveal that rheumatoid arthritis is a relatively more chronic and late onset disorder, since the functional performance of hypothalamo-pituitary-adrenocortical (HPA) axis declines with chronicity and the efficacy of adrenocortical response to return to normalcy becomes impaired.