The study tests the hypothesis that estradiol administration exacerbates the effects of the stress hormone cortisol on cognition and mood for postmenopausal women. This randomized, placebo-controlled, double-blind study was designed to examine the effects of an eight-week trial of transdermal estradiol replacement therapy (0.10 mg/day) in combination with 4 days of oral hydrocortisone (90 mg/day in 3 daily doses of 30 mg per dose) in the last week of hormone therapy on cognition and mood in healthy postmenopausal women. Forty cognitively healthy postmenopausal women were randomized to receive either placebo or estradiol skin patches for 8 weeks. In the middle of the 7th week (day 57), subjects in each group were again randomized to receive either a placebo tablet or an oral hydrocortisone tablet 3x/day for 4 days. Memory testing and blood collection occurred at baseline, at week 4, and again at week 8.