The metabolic effects of a new oral contraceptive Femodene (SHD 356C) containing 75 micrograms gestodene (delta-15-levonorgestrel) and 30 micrograms ethinyloestradiol were studied in two groups of women. Group 1 consisted of women not currently using oral contraceptives; Group 2 consisted of women switching to Femodene from their current oral contraceptive. Changes in lipid metabolism were assessed by measuring serum levels of cholesterol, triglycerides, LDL-C, VLDL-C, HDL-C, HDL2-C and HDL3-C. Minimal changes occurred in lipid metabolism apart from increases in triglyceride concentrations. Women in Group 1 showed a 105% increase in SHBG levels and a 51% increase in caeruloplasmin levels compared to increases of 33% and 2% in women in Group 2. A comparison of the two groups of women suggested that the gestagen in Femodene exerted a less anti-oestrogenic effect than most of the gestagens currently used in oral contraceptives. No significant changes occurred in liver function (assessed by estimation of gamma-glutamyl transferase) or in the coagulation factors, Factor X and antithrombin III. Minor effects on glucose tolerance as assessed by blood glucose and plasma insulin levels were noted. These minimal effects on metabolism, combined with its high efficacy and acceptability shown in clinical trials, makes Femodene an ideal alternative to currently used oral contraceptives.