They are not bad for the epidermis, unless you were to color the area of skin over and over and over. Even if this were to be the case, you're most likely looking at a mild case of dermatitis, but nothing too threatening. In point of fact of this, it takes upwards of a liquid ounce of the fluid to case any type of reaction at all unless you happen to be allergic to propanol, butanol, diacetone, or cresol based alcohols, which are a main ingredient in the marker. The last three are especially noteworthy in that they are industrial grade solvents. You DO NOT want to use King Sized or more industrial intended markers as these mainly contain xylene and cresol, which are quite bad for you in conjunction, but the xylene more so than the other. And lastly, not that it needs to be stated I think, but you NEVER use this ink for tattooing purposes outright!