lead is not the only concern.. in my experience as a potter the ceramic colors in the red part of the spectrum are the ones you will most likely find lead but other chemicals are used for other colors.. if the base glaze tat the colorants are added too are not well formulated and fired than leaching can occur and over time that chemical can get in your system, some don'c come out of your system easy.. its not the chemicals its the porosity of the finished glaze they are suspended in.. I look out for matte glazes on food wear and look for white or clear glazes on the primary food surface (inside the mug) if you want to know if your pretty matte platter that you serve fruit wedges and deviled eggs at the church potluck on is safe.. leave a lemon wedge on the glaze over night... if you take the wedge off in the morning and see an image like a shadow of the lemon wedge on your plate.. it is leaching chemicals. so get one with a white shiny inside