We report the effects of sublingual absorption of a single dose (0.5 mg) of oestradiol-17 beta (E2) in 8 post-menopausal women, on plasma E2 and oestrone (E1), urine elimination of total E2 + E1 and on plasma FSH and LH. The results show that sublingual absorption of E2 occurs and that plasma concentrations of E2 obtained (between 133.2 to 320 pmol/l) in this way were higher than those obtained after percutaneous absorption of a single dose (3 mg) of E2. The ratio E1/E2 in plasma is close to that of pre-menopausal women.