Catgut suture is a type of surgical suture made of twisted strands of purified collagen taken from the small intestine of domesticated ruminants or beef tendon. It is naturally degraded by the body's own proteolytic enzymes. Full tensile strength remains for at least 7 days, and absorption is complete by 90 days. This eventual disintegration makes it good for use in rapidly healing tissues and in internal structures that cannot be re-accessed for suture removal.