A method of sterilization by tubal occlusion using a sclerosis agent, methylcyanocrylate (MCA), was tested in 374 women at 6 centers using 3 different methods of application. The instrument of application was called Femcept; .65 ml of MCA were used in each procedure. The 1st protocol required a single application of MCA, the 2nd required 2 injections 2 months apart, and the 3rd called for a single application of MCA immediately after uterine lavage. In each case another method of contraception was used until hysteroscopy 4 months later demonstrated complete tubal obliteration. A 4th stage of research involved evolution of a new formula of radiopaque MCA which permitted assessment of tubal patency. Tubal closure was shown by hysteroscopy in 93 of the 131 single application cases (75%), 68 of 101 uterine lavage cases (67%), and 123 of 142 double application cases (87%). Among 935 patients treated with all protocols since the beginning of the study but excluding those receiving radiopaque MCA, 22% complained of pelvic pain and 7% of fever 1 month after application, and 2% required hospitalization. Of the 20 women hospitalized, 11 showed signs of genital inflammation. 78% of the 148 cases treated with radiopaque MCA showed bilateral tubal obliteration. The frequency of pain, fever, and hospitalization was the same as for the nonradiopaque MCA group. 23 confirmed and 2 suspected pregnancies have occurred in the 1027 women treated with MCA.