Fifteen patients with laparoscopically diagnosed tubal pregnancy and constant or rising plasma beta-hCG levels were treated with prostaglandin F2 alpha and prostaglandin E2. Prostaglandin F2 alpha (5 mgms diluted in 10 cc of isotonic sodium solution) was injected transabdominally with a 22 gauge spinal needle during laparoscopy into the Fallopian tube. Prostaglandin E2 (500 micrograms ms) was given intramuscularly during three consecutive postoperative days. The treatment was defined as successful if plasma beta-hCG levels declined below the lower limit of detection and no further intervention other than prostaglandin application was required. The treatment was successful in eight patients. Six patients underwent laparotomy and salpingotomy because of rising beta-hCG levels. None of the treated patients displayed any adverse reactions following prostaglandin F2 alpha application. One patient underwent explorative laparotomy during the second postoperative day because of lower abdominal pain. During operation, no pathological change could be found. This patient was excluded from the study. In the group treated successfully (n = 8) seven out of eight patients had beta-hCG levels below 2500 mlU/ml preoperatively. In the unsuccessfully treated group (n = 6), four out of six patients had beta-hCG levels above 2500 mlU/ml preoperatively. Mean duration of beta-hCG decline to 10 percent of the maximum preoperative value was 15.8 +/- 8.64 days (mean +/- S.D.). Postoperatively, hysterosalpingography was performed in six out of eight successfully treated patients after three menstrual cycles (one patient had an intrauterine pregnancy, one patient refused written consent). The Fallopian tubes were patent bilaterally in all six patients.