"20/20" crew waited in this hotel, for the arrival of the man who calls himself the archbishop. 59-year-old mark grenon had no idea "20/20" was on his tail. and over the next two days we watched with hidden cameras rolling as the archbishop went about his business, making is a miracle cure for virtually any disease. >> this is our sacrament. >> reporter: preying on the desperate and vulnerable, including women with breast cancer and the parents of autistic children. >> i would like to see somebody go get these people. >> reporter: on this day, the archbishop's cathedral was a hotel conference room. his vestments, a black leather jacket and a bejeweled panama hat. and his sermon, to people who were charged $450 a head, seems book of shams. >> i got people curing some major stuff just from that. from prostate cancer, to brain cancer, to autism. >> reporter: all by drinking what he calls the sacraments of the genesis ii church of health and healing, available for anyone who makes what is called a donation. >> it's like watching a really good magician's show. >> reporter: dr. steven novella, of the yale sc

overseen in the us, by a man who says he's an archbishop, mark grenon. archbishop mark grenon: this is our sacrament. claiming that what's in this glass is a miracle cure for the most serious of diseases. to find out what's in the miracle cure, we ordered a shipment, $150 dollars for these small bottles. and took them to a respected testing laboratory. nothing miracul essentially a kind of chlorine. paul wang: (12:21:23) mms is an industrial chemical. it's an industrial bleach. in fact, look what happened when we poured some of it undiluted on to a pair of jeans, the denim turned white through both pant legs. even at the prescribed, much smaller dose, experts warn it's a danger for anyone to drink it. dr. paul wang: (12:21:45) the fact that anybody would suggest that you should give this to somebody//is ridiculous. but to the outrage of medical professionals, the church,slicks aggressive pushing the miracle cure, shipping millions of bottles to people all over the world. including people suffering from breast cancer. dr. jennifer ashton: i think that kind

overseen in the us, by a man who says he's an archbishop, mark grenon. archbishop mark grenon: this is our sacrament. claiming that what's in this glass is a miracle cure for the most serious of diseases. dr. steve novella: (01:03:03) it's like watching a really good magician's show. on this day, as abc news watched, the archbi conference room in southern california. his vestments: a black leather jacket and a bejeweled panama hat and his sermon, to a congregation that was charged $450 a head to be there, seems to have come right out of the book of shams. archbishop mark grenon: i got people curing some major stuff just from that.// from prostate cancer, to brain cancer, to autism. to find out what's in the miracle cure, we ordered a and took them to a respected testing laboratory. nothing miraculous about it, essentially a kind of chlorine. paul wang: (12:21:23) mms is an industrial chemical. it's an industrial bleach. in fact, look what happened when we poured some of it undiluted on to a pair of jeans, the denim turned white through both pant legs. eve

archbishop. it's called the genesis ii church of health and healing. and 59-year old mark grenon is the archbishop. claiming that what's in this bottle is a miracle cure for virtually any disease. sot archbishop mark grenon: "from prostate cancer, to brain cancer, to autism." but as we found after buying and testing some of the miracle cure, called mms, there is nothing miraculous about it. basically a form of chlorine. it's an industrial bleach." in fact, look what happened when we poured some of it undiluted on to a pair of jeans. to the outrage of parents, that's just what's being given, in much smaller doses, to children with autism. sot roland eggar: "you are doing it at the expense of these defenseless children. how can you not call that evil?" the fda has received reports from severe, unstoppable vomiting and diarrhea caused by drinking it. and the husband of sylvia nash says she died after taken a few drops of the miracle cure, told it would prevent malaria. ot doug nash: "mms did kill my wife. there's no question in my mind." an autopsy could not determine her cause of d

archbishop. church of health and healing. and 59-year old mark grenon is the archbishop. claiming that what's in this bottle is a miracle cure for virtually any disease. sot archbishop mark grenon: "from prostate cancer, to brain cancer, to autism." but as we found after buying and testing some of the miracle cure, called mms, there is nothing miraculous about it. basically a form of chlorine. sot paul wang: "mms is an industrial chemical. it's an industrial bleach." in on to a pair of jeans. to the outrage of parents, that's just what's being given, in much smaller doses, to children with autism. sot roland eggar: "you are doing it at the expense of these defenseless children. how can you not call that evil?" the fda has received reports from across the country of violent, severe, unstoppable vomiting and diarrhea caused by drinking it. and the husband of sylvia nash says she died after taken a few drops of the miracle cure, tol ot doug nash: "mms did kill my wife. there's no question in my mind." an autopsy could not determine her cause of death. nats but the claims tha

archbishop. it's called the genesis ii church of health and healing. and 59-year old mark grenon is the archbishop. claiming that what's in this bottle is a miracle cure for virtually any disease. sot archbishop mark grenon: "from prostate cancer, to brain found after buying and testing some of the miracle cure, called mms, there is nothing miraculous about it. basically a form of chlorine. sot paul wang: "mms is an industrial chemical. it's an industrial bleach." in fact, look what happened when we poured some of it undiluted on to a pair of jeans. to the outrage of parents, that's just what's being given, in much smaller doses, to doing it at the expense of these defenseless children. how can you not call that evil?" the fda has received reports from across the country of violent, severe, unstoppable vomiting and diarrhea caused by drinking it. and the husband of sylvia nash says she died after taken a few drops of the miracle cure, told it would prevent malaria. ot doug nash: "mms did kill my wife. there's no question in my mind." an autopsy could not determine her cause of de

sot archbishop mark grenon: "from prostate cancer, to brain cancer, to autism." but as we found after buying and testing some of the miracle cure, called mms, there is nothing miraculous about it. basically a form of chlorine. sot paul wang: "mms is an industrial chemical. it's an industrial bleach." in fact, look what happened when on to a pair of jeans. to the outrage of parents, that's just what's being given, in much smaller doses, to children with autism. sot roland eggar: "you are doing it at the expense of these defenseless children. how can you not call that evil?" the fda has received reports from across the country of violent, severe, unstoppable vomiting and diarrhea caused by drinking it. and the husband of sylvia nash says she died after taken a few it would prevent malaria. ot doug nash: "mms did kill my wife. there's no question in my mind." an autopsy could not determine her cause of death. nats but the claims that the miracle cure actually harms people was not something the archbishop wanted to talk about. brian ross: are you harming people with

and 59-year-old mark grenon is the archbishop. claiming that what's in this bottle is a miracle cure for virtually any disease. >> from prostate cancer, to brain cancerto after buying and testing some of the miracle cure, called mms, there is nothing miraculous about it. basically a form of chlorine. >> mms is an industrial chemical. it's an industrial bleach. >> reporter: in fact, look what happened when we poured some of it undiluted onto a pair of jeans. to the outrage of parents, that's what the archbishop says should be given to children with >> you are doing it at the expense of these defenseless children. how can you not call that evil? >> reporter: the fda has received reports from across the country of violent, severe, unstoppable vomiting and diarrhea caused by drinking it. and the husband of sylvia nash says she died after taking a few drops of the miracle cure, told it would prevent malaria. >> mms did kill my wife. there's no question in my mind. >> reporter: an autopsy could not determine her cause of death. but the