Hubby picked up a new multivitamin a few weeks ago and of course he read the ingredients to make sure it was OK. A couple weeks later I read the ingredients out of curiosity/boredom/being nosy? Maybe a bit of all. I noticed one of the ingredients was barley grass which popped up a big red flag for me, of course. A quick search online didn't give me any definitive answers. Some things said it should be OK since it's technically the grain that contains the gluten while others said unless it states gluten free to avoid it. So I used the last of my EZ Gluten tests and sure enough, positive for gluten. At least we now knew why Hubby had been feeling so tired lately. I've read before that wheat grass is safe but after this it's for sure in my avoid at all costs category.
Another sneaky gluten containing ingredient can be millet. Of course it's a naturally gluten free grain but according to an article in the September Gluten-Free Living magazine millet flour was found to have high (in the 300 ppm range) levels of gluten in packages that were not labeled gluten free. They believe this may be due to cross contamination from crop rotation of millet with winter wheat. So if you use millet flour be sure it states gluten free on the packaging.