I wouldn't take the chance mommy even though some women do it doesn't make it safe.
It is never safe to drink Castro oil. I don't care what anyone says it can be very harmful for the baby. It forces your body to dehydrate which is why it causes contractions. Plus it makes you sick and gives you and the baby diarrhea. And if your baby takes a bowl movement it can be terrible for its lungs but worse if it has diarrhea and does it. Honestly at this point you are just now full term you shouldn't be doing anything extreme to get labor started. Your baby will come when it's ready no matter what you do but Castro oil is the worst thing you can do for yourself and baby. Just stay active go on walks and have sex, bounce on a birthing ball and just wait it out, your almost there.