Keep off the grass. And also the GRAS. The first one you've probably heard of. The second one is Generally Recognized as Safe. The vague language should be a tip-off that GRAS doesn't mean that it's been confirmed as good for you. The dose makes the poison, and that's true for a lot of things that are GRAS, especially cosmetics. Still, nature is what brought us lead, arsenic, and asbestos, so try to make informed decisions rather than just living "naturally".