Don't do it! I drank a castor oil cocktail when I was 10 days overdue with my son. It gave me intense contractions, 2 minutes apart for 27 hours, vomiting and diarrhea, but I didn't dilate past 1cm. Ended up with an emergency csection. I had tried acupuncture 3 times, and everything else under the sun. When they are ready to come out, they will come out. Good luck!