As parade and bar-goers know, the color green saturates everything in sight on St. Paddy’s Day — including food and drink.

But what may seem like a harmless way to celebrate all things Irish (yes, we’re talking about you, green beer and green milkshakes) is in fact not all that bonny for the planet or your body, research shows.

Industrial artificial green food coloring — known variously as FD&C Green No. 3 and Fast Green FCF — is derived from petroleum, a limited resource, and contains coal tar. It’s also associated with an increased risk of certain cancers and hyperactivity in children, according to a study released by the Center for Science in the Public Interest.

The European Union requires a warning label on foods containing dye, including FD&C Green No. 3, but in the U.S. it remains one of nine synthetic dyes FDA-approved for food processing.

Still thirsty for a green beer?

Try coloring up your drink with a naturally derived food dye instead. India Tree dyes use red cabbage, turmeric and beets to create intense shades of blue, yellow and red. (Remember from grade school? Blue + yellow = green.) Chefmaster sells ready-made green derived from red cabbage and beta carotene.

If you’re game for the DIY route, check out these instructions for fruit- and veggie-based homemade dye from the Natural Resources Defense Council’s Simple Steps site. (It works — the city of Chicago, which dyes its river green every St. Patrick’s Day, uses vegetable dye to get the job done.)

As for that hangover, though, you’re on your own.

This story was originally published on March 10, 2011. It was updated on March 18, 2018.