Ethicon Sutures. Chromic Gut. 636H 3-0 FS-2 27" 36/Box The chromic gut suture is an absorbable, sterile surgical suture composed of processed and purified connective tissue made mostly of collagen from either the serosal layer of beef or the submucosal fibrous layer of sheep intestines. Best use includes general soft tissue approximation or ligation. 3/0, 27" Chromic Gut Absorbable Suture with Reverse Cutting FS-2 Needle (3/8 circle), box of 36 suture sets.