Interestingly, Papaya seeds maybe an effective natural birth control measure.
From The Tao Of Health, Sex, and Longevity:
For thousands of years, the young women of Polynesia have enjoyed complete and uninhibited sexual freedom prior to marriage, with no worries about unwanted pregnancy. Their secret is to eat a few handfuls of papaya seeds every day. The active ingredient responsible for their freedom from pregnancy is vitamin B17, more popularly known as laetrile, the controversial drug banned in the United States due to unproven claims that it can prevent and help cure cancer. (4571–4574)
From the queerly named book Herbal Abortion: the Fruit of the Tree of Knowledge
If you made love with a man during your fertile time (for example, days 10–16 in a 28 day cycle), and you do not wish to be pregnant, here is what you do:
1. After unprotected intercourse on a potentially fertile day, begin eating 5–10 apricot kernels 3 times a day. Continue this until your period comes. This prevents implantation. (The same effect can be achieved with high levels of Vitamin C in this way. Use more than 10 grams per day.)
I discuss this further in a podcast
