Aclopil MR is a combination of two pain relieving medicines (Aceclofenac and Paracetamol ) and a muscle relaxant ( Chlorzoxazone). The pain relieving medicines work by blocking the release of certain chemical messengers in the brain that cause pain and inflammation (redness and swelling). The muscle relaxant works on the centers in the brain and spinal cord to relieve muscle stiffness or spasm, thereby improving muscle movement.