Catgut is prepared from the submucous coat of sheep or cow intestine. Plain catgut is rapidly hydrolysed in tissues and loses its integrity within a few days and should only be used in tissues where this is not a disadvantage.

Catgut has a variable reasorption rate, and associated with greater tissue reaction than synthetic materials. Importance of this is the unpredictable tensile strength, hence should not be used alone for abdominal closure