He was not taking the bloodroot internally. Did 2 applications of it on a spot on his chest that we think was fungal or viral about 3 weeks ago, cleaned it up nicely. The black/dark gray areas on his teeth appeared almost immediately after using the colloidal/ionic silver (10ppm). My hunch based on looking at the stains is that he has some porosity where the silver particles absorbed, settled and oxidized. It looks slightly better this morning than when he showed it to me yesterday.