Which Poppy Seeds Are Used for Cooking?

Is it okay to use any of the different varieties of poppies for their seeds in cooking? Or, can only the corn or opium poppies be used?

As far as we know only the corn and opium poppy seeds are edible. Always check the latin name of the poppy whose seeds you want to eat, because several species are sold for garden use. Corn poppy is Papaver rhoeas and opium poppy is Papaver somniferum. Don't take any chances with unknown species because some may not be safe to consume.