Fybogel is a sugar-free fibre supplement derived from the seed husk of the Ispaghula plant, one of nature's richest sources of dietary fibre. Fybogel High-Fibre Supplement is an easy-to-use and pleasant - tasting way to increase the fibre in your diet, helping your digestive system work more efficiently and gently relieving constipation without straining, discomfort or unnatural urgency, helping to restore and maintain regularity. Fybogel works by forming bulk in the digestive system. It does this by absorbing water in the large intestine, hence softening and increasing stool bulk.