is food coloring bad for cats?

I got home from work earlier to find that my handsome boy had some how gotten ahold of a box of food coloring, chewed it up, and proceeded to roll in it. I tried bathing him but it didn't help. He had to have ingested some of it since the containers were destroyed. It's is going to harm him? Do I need to take him to the vet?

No, food coloring meant for food is not harmful at all.

Might not be so nice to look at on his fur but............