Synthetic food pigment is made from aniline dye separated from coal tar, so it is also called coal tar pigment or aniline pigment, such as synthetic amaranth, tartrazine and ponceau 4R. Occasionally eating food added with a certain amount of synthetic food pigment will not cause poisoning, diarrhea and other reactions. 
Eating food added with a small amount of natural edible pigment will not affect human health.
 it is allowed that people can eat food added with a small amount of synthetic pigment.