Diluting the iron supplement in a couple ounces of juice or water can help prevent stains from occurring. Try adding the supplement to orange juice since vitamin C facilitates iron absorption. Do not add it to milk though because milk can interfere with proper iron absorption. As an additional prevention step, reduce contact of the diluted supplement mixture with the front teeth by having the toddler use a straw or sippy cup. However, watch closely to make sure all of the liquid has been consumed.