December 22, 2017 Unauthorized product alert: Ultra Pure Colloidal Silver health risks Health Canada is advising Canadians, especially children and pregnant women, not to use the unauthorized product Ultra Pure Colloidal Silver by ECG Naturals because it may pose a serious risk to health. Consumers taking this product are at risk of developing a condition called generalized argyria, which is the permanent bluish-gray discolouration of the skin, eyes and nails. At this time, there is no scientific evidence that supports the use of colloidal silver for any specific disease or condition in humans. The product may have been sold at retail stores across Canada.