One hundred eighty-one women received 30 mug of ethinyl estradiol plus 150 mug of d-norgestrel as an oral contraceptive for 21 days and then received no tablets for the next seven days for a total of 1,488 cycles. There were no pregnancies. Cycle control was good to excellent. Menstrual cycles lasted 25 to 32 days in 96.2% of treatment cycles. Menstruation lasted three to five days in 93.2% of the cycles, and it began three to five days after the last day of medication in 79.1%. The menstrual flow was moderate in 87%. Breakthrough bleeding occurred in 2.0% of treatment cycles, spotting in 0.1%, and amenorrhea in 0.8%. The incidence of adverse subjective symptoms was minimal and significant increases compared with the pretreatment cycle were noted only for nausea in the first two cycles and for nervousness in the second cycle of treatment. Overall incidence of nausea was 3.2% of treatment cycles.