There are apparantly a lot of people taking it. I have not heard of any deaths from overdose and it is not carcinogenic. You won't find "proof" of anything here. Far as I know there is not anyone on this debate forum that has the specific knowledge required to judge whether or not Miracle-Mineral-Supplement is safe for humans at the dosages indicated on the Miracle-Mineral-Supplement websites. I could tell you what they are qualified to do but that would be like letting a fox in a henhouse...just start a lot of squawking. So if your friend is determined to try it...and stays at or under the 15 drops 3 times per day the worst that will happen is he/she will get a case of diahrrea or possibly vomit. For the record I do know someone who has been at that level for many months with no ill effects.