This supplement, from the seed of the plantago or plantain plant, is safe for GI cleansing. In the colon, psyllium adds bulk to stools, which then press against the colon wall, triggering nerves that signal the urge to go; the water taken with psyllium also softens stools and lubricates their passage. In addition to aiding the digestive tract, the soluble fiber in psyllium is similar to oat bran in its ability to reduce cholesterol. The usual dose is about 7-5 grams per day. To avoid blockage, it's important to take psyllium with 8 to 12 ounces of water followed by more water throughout the day.