The list of grains forbidden to you if you have celiac disease or gluten intolerance is a lot shorter than the list of grains you can eat. That's the good news.
And the other part of the optimistic picture is that bad grains go by a name, so you can identify them when you see them. The grains you need to avoid on a gluten-free diet are:
Barley and its derivative, malt (take malt vinegar out of your diet too, along with malted milk and those chocolate-covered malt balls — sigh).
Oats because they’re frequently contaminated with wheat and other grains as they’re processed.
Rye and triticale, which is a hybrid of wheat and rye.
Wheat, which has several names and varieties. Beware of aliases like flour, bulgur, semolina, spelt, frumento, durum (also spelled duram), kamut, graham, einkorn, farina, couscous, seitan, matzoh, matzah, matzo, and cake flour.
Beware substituting spelt: Often marketed as a “wheat alternative,” spelt is not even remotely gluten-free.
You need to avoid (or at least question) anything with the word wheat in it. This includes hydrolyzed wheat protein, wheat starch, wheat germ, and so on. Wheat grass, however, like all grasses, is gluten-free.
You have lots of choices for gluten-free grains and starches. Even if you’re an old pro who’s been gluten-free for years, some of these may be new to you.
Amaranth
Arrowroot
Buckwheat/groats/kasha
Chickpeas (garbanzo beans, besan, cici, chana, or gram — not to be confused with graham, which does have gluten)
Corn (You may run across different names or forms of corn that are gluten-free in addition to plain ol’ corn. They include grits, hominy, masa, masa harina, harinilla (blue corn), atole, maize, polenta, corn gluten, and of course, cornstarch, corn flour, corn bran, and cornmeal.)
Garfava
Job’s Tears
Mesquite (pinole)
Millet
Montina (Indian ricegrass)
Potato
Quinoa (hie)
Ragi
Rice (Remember that glutinous rice does not contain gluten! Glutinous rice, also called sweet rice or mochi, is made by grinding high-starch, short-grain rice. Glutinous rice thickens sauces and desserts in Asian cooking and is often the rice used in sushi.)
Sorghum
Soy
Tapioca (gari, cassava, casaba, manioc, yucca)
Taro root
Teff