Hi, My understanding is that for cancer B17 works as a sugar coated cynadie pill and is found in Almond kernels. The rationale is that the cancer cells have a high demand for sugar/ energy and so attract the B17 and then get wiped out by the cynide.
I'm not even sure whether its available in Australia and as Julie has already mentioned there have been cases of cynaidde poisioning. I had some genetic testing done and it was one of the supplements identified as being effective in managing my cancer - hence i did some research but decided to go with the other supplements.
I also chose not to take Tamoxifen as the absolute (rather than relative) reduction in risk in my case was only a couple of % so when i weighed up the option of certain menopause vs slight reduction in risk and considered the 'sampling error' I opted out - but as Julie says, there are many folk who have opted in.
Not sure whether you've seen the book Five to Thrive by Dr Lise N Alschuler and Karoln A Gazella - i found it very helpful
All the best, Hazel