Two estradiol (E2) transdermal patches releasing 25 micrograms/day E2 (D-25) or 37.5 micrograms/day E2 (D-37.5) were compared to a placebo patch on 156 patients in natural or surgical menopause suffering from at least 5 hot flushes per day, randomly and blindly assigned to three parallel groups of 52 patients each, to be treated continuously for 12 weeks, without progestin opposition. "Responders" (patients with less than 3 hot flushes per day at the end of treatment), were 82% and 90% under D-25 or D-37.5, respectively, both significantly (p < 0.001) more than under placebo (44%). Comparable efficacy was observed on severity of hot flushes, Kupperman Index and on the self-rated efficacy. Systemic adverse events occurred in 10%, 10% and 8% of patients, respectively, under D-25, D-37.5 or placebo. Occasional mild and transient itching and/or erythema on the site of application was reported by few patients and did never require discontinuation of application. In conclusion D-25 and D-37.5 were significantly more effective than placebo in relieving climacteric symptoms and were systemically and locally as well tolerated as placebo. D-25 (Demestril 25) releasing 25 micrograms/day E2 can therefore be recommended for low-dosed estrogen replacement therapy.