A new gel for local application of prostaglandins has been elaborated. The new gel, based on a lyophilized prostaglandin E2 (PGE2) starch powder, seems to have solved most of the pharmaceutical and clinical problems associated with local administration of prostaglandins. In a randomized double-blind study, 50 nulliparous patients with an unfavorable cervical state at term were given 2 ml gel containing 0.5 mg PGE2 (PGE2 gel) or gel without PGE2 (placebo gel). The gel was deposited into the cervical canal. Among patients given PGE2 gel, 11 of 25 had induced labor, delivering without further stimulation within 24 hours. In patients given placebo gel, 2 of 25 were delivered with 24 hours. This difference is statistically significant (P less than .01). Patients undelivered after treatment with PGE2 gel achieved a considerable and statistically significant improvement of cervical score, whereas in patients in whom labor was not induced successfully by placebo gel treatment no significant changes in cervical score were registered. In a subsequent open study another 70 term patients of varied parity were given 0.5 mg PGE2 gel. Thirty-eight patients (54%) had successfully induced labor. Among the remaining undelivered patients, considerable ripening of the cervix occurred. Thus, the cervical score changed from a mean of 3.2 prior to treatment to a mean of 6.5 by 24 hours after treatment. Gastrointestinal discomforts were not observed. Signs of uterine hyperstimulation were registered in 1 patient.