I wish I could reference the scientific article I read this in - but it was 24 years ago. What I can tell you is I went 23 days past my due date. I tried many methods before reading the article that said they found that many women naturally get diarrhea at the onset of labor.
My doctor didn't believe my due date because she was small. But there was only one conception event. I knew with my first child I had to be induced and requested it but she said she only would after I had 6 hours of regular contractions. I tried spicy food, acupressure, walking, hot bath. Nothing worked.
I had a desperate urgency feeling that was coming from within me yelling at me to get her out NOW! So, next I drank 1/2 a bottle of caster oil (around 1/3 cup- it was too much) It worked but gave me bad cramps and water like runs.. I got contractions 3 minutes apart for exactly 6 hours.
The contractions only opened me 1.5 cm so she induced and 7 hours later I was finally allowed to push. The urgency feeling was still pounding my brain so I crossed my arms tight under my breasts and curled my upper body against them - using them to push her down and out in only 2 pushes. (A method I figured out during my son's delivery)
When she came out she was placed on my stomach. The doctor went to try tug on the cord to see if the placenta was ready to come out and it pulled right off. The placenta was completely disintegrated. She had to scoop it out with her hand. When she lifted it up it was thin, full of holes and falling apart. She said if she had been born 15 minutes later - she would have been stillborn. She determined that she had only been half attached the whole time. I didn't go into labor because my body didn't know I was pregnant. (No Braxton hix. No morning sickness, didn't show until after 7 months) Her skin hung on her as she'd lost weight because the placenta was failing. She weighed 6lbs 3 oz and 18.5" long. Born at 11:11pm. I named her Talia, (the 10th angel that helps the sun across the sky)
Long story short.. caster oil works.
Re: What really induces labor naturally is diarrhea.
Your information about diarrhea causes labor induction and the use of Caster Oil is pure coincidence for you. That can be very dangerous and should be discussed w/ a doctor for ANYONE to do. I can not imagine purposefully giving myself the runs and trying to push baby out w/ the runs! Bad enough (for the doctor) that it does happen naturally w/ some women but to force it w/ Caster Oil is not cool - and a old wives tale.