Health Canada issued a warning Friday after it discovered another website selling MMS - a potentially toxic and dangerous substance - as a "miracle" supplement.

The agency said it has received four reports of adverse reactions, including one life-threatening reaction, to MMS, also known as Miracle Mineral Solution or Miracle Mineral Supplement.

Sites selling MMS list sodium chlorite as its active ingredient and claim it can cleanse the body of toxins.

But sodium chlorite is only authorized in Canada for veterinary use as a germicide and as a hard-surface disinfectant.

Products purporting to contain 28% sodium chlorite solution, if taken as directed, would deliver approximately 200 times more sodium chlorite than the tolerable daily intake established by Health Canada, the agency said.

MMS may cause serious health problems that include poisoning, kidney failure and harm to red blood cells that reduces the ability of the blood to carry oxygen, Health Canada said. It may also cause abdominal pain, nausea, vomiting, and diarrhea.

The agency hasn't authorized any products containing sodium chlorite for oral ingestion.