Mesotherapy is a new treatment for horses with soreness in the neck and/or back. It acts to simulate the mesoderm, the middle layer of the skin. This can relieve a wide variety of ailments. The principle is based on the theory of gait control of pain that originates from the dorsal horn of the spinal cord. Types I and II nerve fibers coming from the skin have collateral fibers that can inhibit the conduction of information from deep structures of the same spinal segment to the brain.