I'm assuming you mean you're three days past your due date? You really need to talk to your doctor before you do anything. You should not try to induce your labor without your doctor. Your doctor is the one who knows not only your health background, but also will be able to tell you better than anyone online if your baby is even ready to come.

If you are three days passed your due date, as justcurious mentioned, you aren't actually overdue yet. Overdue is when you move passed 42 weeks, and even then some women will naturally go a bit longer.

I know it can be challenging at the end of pregnancy, but unless there is a true medical reason for baby to be born before they would come on their own, it is unwise to try and get things going. The only time I would suggest any methods would be if a medical induction was already scheduled and a mother was hoping to avoid that.

Castor oil works for some women, but many others find the only result is an upset stomach, cramping, and diarrhea.

There are less invasive ways to see if labour can be started. Nipple stimulation (due to the release of oxytocin) and pressure points (spleen 6 and hoku) are two that sometimes work for some women... although they tend to work better once labour has already begun. Frequent intercourse may help as semen has prostaglandins in it.

None of these things will work well if your body is not ready for labour to begin. Even medical inductions do not go smoothly if the woman's body is not ready to be induced.

Do your best to wait a bit longer... find ways to pamper yourself. If you get to a stage where your doctor starts talking induction because you haven't gone into labour yet, let us know.