There is only one substantiated piece of research that has been performed on an extract of one species of "noni," that was done on mice, that showed that it might have some anti-cancer properties.
Substantiated rumor is that true Polynesian people cut the stuff down and burn it, seeing no medicinal value in it what-so-ever.
The product is sold in typical MLM fashion, with high powered babble of miracle stories of alleged illnesses being cured.
Anything in this universe is possible, and it is possible that some people may have had a 'cure' to their illnesses, we will never know about the many people who had no benefit, or were made sicker as a result of taking any of these 'miracle products.'
As somebody who is living with a life-threatening autoimmune disease, prior to startig to Eat Right 4 My Type, I spent thousands of dollars on both allopathic and natural remedies. None cured me, a few helped (barely), most had no effect, and a few made me sicker.
I eventually issued a challenge to MLM'ers on UseNet. Put up or shut up. Send me your product for free. If it works, and I'm cured, I'll pay you 5x the going rate, and become a professional mouthpiece for your product, grattis.
Only one taker, for some aloe juice that was so full of preservatives and artificial flavorings I declined to try it.
Enough of my rambling. Suffice it to say, I believe that it is what you do, not what you take, that leads to health. In this case, it's EATING the diet for our blood types.