Tree Harvest Psyllium Husks is an excellent source of natural fibre and a great addition to any health plan. Psyllium is a form of fibre made from the husks of the ispaghula seed. They tend to be used in detox programmes. It works by absorbing water into its mass and goes through the digestive track, clearing and cleaning as it goes. This helps to bulk the stool and works to ease constipation or diarrhoea.