The use of Gemeprost vaginal suppositories has been evaluated in a trial for in-duction of the cervical dilatation in non-pregnant women. 30 voluntary patients, 22 nulliparous and 8 pluriparous, had to be subjected to biopsy of the endometrium; 24 were treated for the control of sterility and 6 for menstrual perimenopausal di-sorders. The biopsies of the sterility control were effected in the second half of the cycle, generally without having recourse to narcosis. A single Gemeprost pessary containing 1 mg of 16, 16-dimethyl-trans- PGE, methyl ester was intravaginal administered, deeply into the posterior fornix, 3 hours before the biopsy. All the observed side effects presented a modest intensity: cephalalgia 6.6% (no. 2), gastral-gia 3.3% (no. 1), vaginal burning 6.6% (no. 2). No significant variation of vital function para-meters was recorded. In conclusion this type of preparation of the cervix has permitted us to achieve a more gra-dual dilatation and to prevent the traumata of the cervico-isthmic system due to forced mecha-nical dilatataions by the exclusive use of Hegar’s dilators.