A so-called "miracle" treatment that claims to cure autism has been making the rounds online for years now.
But experts say the mixture is actually a form of industrial bleach, and it can cause serious health problems if ingested.
"The fact that anyone would suggest that you should give this to somebody is ridiculous. This is scary, dangerous stuff," Dr. Paul Wang, senior vice president of Autism Speaks, told ABC.
The treatment is commonly known as Miracle Mineral Solution, Master Mineral Solution or MMS.
Its main promoter is the Genesis II Church of Health and Healing, an organization that claims to be a "non-religious" online church.
The Genesis II Church urges its followers to take MMS either orally or through enemas to treat autism and a slew of other ailments, including cancer, acne, hepatitis and AIDS.
But health officials around the world have found the mixture contains sodium chlorite, a chemical that's primarily used as a bleaching agent and disinfectant.
Ingesting the recommended dosage of MMS can cause severe vomiting, diarrhea and dehydration, among other dangerous health problems. The Genesis II Church claims these side effects are a sign that the "cure" is working.
But experts say it's torturing children with autism, who often have trouble communicating when something is hurting them.
"Families are very vulnerable often straight after diagnosis, and what they need is support and advice. There is no evidence that this substance is helpful at all," Carol Povey of the National Autistic Society told the BBC.
Health officials are urging anyone who has used MMS to contact a health care professional immediately.