Almost every cat scratching post available is constructed using the sisal material either as sisal fabric or twisted sisal rope. One downside to using other natural rope fibers is that the fibers will dislodge as the cat scratches over time, creating a sharp surface. Abrasive and toxic rope materials will harm the cat. Since sisal is antimicrobial and pet-friendly, it is an excellent choice for cat scratching posts and bird toys. Sisal rope is the best choice for any cat scratching post or cat tree. Cats love the textured feel of sisal rope and fabric.