Catgut USP 4/0 - Distinctive Characteristics of Catgut suture: Catgut suture a natural absorbable suture and is obtained by longitudinally slitting the intestinal submucosa of sheep and goat, twisting the ribbons and joining them in wet condition giving monofilament finish. Catgut chromic sutures are absorbed by enzymatic hydrolysis and starts losing tensile strength from 18-21 days on implantation. Catgut sutures are treated with chromic salt to enhance absorption period and reduce any adverse tissue reaction. Catgut sutures are available in dark brown colour. Sterilized by sterilizing fluid containing EO, isopropyl alcohol and distilled water.