Health Canada is asking retailers to remove stock of Colloidal Silver Water 20ppm, a nutritional supplement marketed as a treatment for infections, because it may pose a serious health risk to consumers.

The federal agency said Monday consumers should return the product — which can be taken orally and used as drops in the eye, ear and nose — to the retailer.

The product, distributed by Vancouver-based SilverHealth Products Inc., may not be sterile, Health Canada warns. Consumers who use the product as eye drops may be at risk for infection.

Health Canada also warns users that the product, which has not been authorized for sale in Canada, exceeds the daily limit of silver for infants, children and adults. If users have been taking the product orally, silver may accumulate in the body and cause a condition known as generalized argyria characterized by bluish-grey discoloration of the skin, eyes and nails.

Health Canada says the company has failed to comply with requests to withdraw the product from the marketplace.

The product was sold in stores and online. Consumers with questions can contact Health Canada at (613) 957-2991, or toll free at 1-866-225-0709.