Psyllium, derived from the plants known as ispaghula, Plantago psyllium, or Plantago ovata, is a primarily soluble, bulk-forming fiber supplement.[1][2][3][4] Psyllium is commonly used in clinical settings for chronic constipation, because it tends to be gentler than stimulant laxatives.[5] Currently, psyllium has a generally recognized as safe (GRAS) status in the US as a food additive.
Psyllium fiber is made of indigestible carbohydrate chains consisting of approximately 15–25% fermentable components, with the remainder being poorly fermentable or unfermentable in the gut.[6][7] The main carbohydrates found in psyllium are arabinose and xylose, which combine to form arabinoxylans — a complex fiber which may contribute to a healthier gut microbiome.[6][7][8]