A prospective, randomized, controlled study was carried out to investigate the dilating and softening effect on the cervix of prostaglandin F2-alpha gel administered intracervically and of prostaglandin E2 tablets administered orally. A total of 581 patients were included in the study: 149 received 2.5 mg prostaglandin F2-alpha in gel form intracervically, 150 received 1 mg prostaglandin E2 in tablet form orally, 138 were given placebo gel and 144 no medication at all. In the groupgiven prostaglandin F2-alphagelintracervically, success was achieved in 85.8% of patients and partial success in 8.8%. In the group given prostaglandin E2 tablets orally, the results were successful in 29.4% and partially successful in 40.6%. The incidence of side effects in the group given prostaglandin F2-alpha gel was rather high – 53%. The results show that prostaglandin can bring about a certain softening of the cervix, but side effects cannot be ruled out. Nevertheless, priming of the cervix is to be recommended in young primigravidas.