Psyllium husks powder

Even Dr. Oz made it into the article!

The characteristics of psyllium seed husks make them useful for any treatment that requires improvement or maintenance of transit time in the gastrointestinal tract, since the inert bulk of the husks helps provide a constant volume of solid material irrespective of other aspects of the diet or any disease condition of the gut.
Over-the-counter laxatives and fiber supplements such as Metamucil, Serutan, Effersyllium, and Isabgol have psyllium husks as their main ingredient, in finely chopped or powdered form. The husks can be consumed as-is (with plenty of water or other fluid) with much the same effect. Psyllium can also be added to food or drink to boost the fiber content of the diet, and some cereals (Bran Buds, Heartwise) contain it.Psyllium husks are used to relieve constipation, irritable bowel syndrome, diverticular disease, and diarrhea. They are used as a regular dietary supplement to improve and maintain regular GI transit.
Some recent research is also showing them to be promising in lowering cholesterol and controlling diabetes.Dr. Mehmet Oz recently brought popularity to psyllium seed husks on a November 2006 episode of The Oprah Winfrey Show, on which he revealed that he puts them in the blueberry shake he makes for his family every morning. Dr. Oz claims that eating them daily with your breakfast keeps you feeling less hungry all day, may promote weight loss, and has longterm health benefits.