What is Green 3?
Green 3 also known as Fast Green FCF and FD&C Green No. 3, is a sea green triarylmethane food dye. 
This substance has been found to have Tumorigenic effects in experimental animals, as well as Mutagenic effects in both experimental animals and humans. It furthermore risks irritation of eyes, skin, digestive tract, and respiratory tract in its undiluted form. 
Synthetic food dyes have been suspected of disrupting children's behavior since the 1970s, when Dr. Ben Feingold, a San Francisco allergist, reported that his patients improved when their diets were changed. Numerous controlled studies conducted over the next three decades in the United States, Europe, and Australia proved that some children’s behavior is worsened by artificial dyes, but the government did nothing to discourage their use and food manufacturers greatly increased their reliance on them.