Psyllium husk comes from the small seeds of the Plantago ovata plant. Because it is classified as a seed, not a grain, it does not have any gluten in its natural state. Some psyllium husk supplements, however, may contain small amounts of gluten, depending on other ingredients added during the manufacturing process.

Plain psyllium husk and ground psyllium husk powder are gluten-free, meaning they have less than 20 parts per million of gluten, as defined by the U.S. Food and Drug Administration. Some supplement manufacturers add wheat flour to psyllium husk supplements, though. It’s used as a binding agent in chewable wafers and pills. Always read the label carefully if you’re sensitive to gluten, no matter which form of psyllium husk you take. The label should state “free of gluten,” “no gluten,” “gluten free” or “without gluten.”