Mesotherapy is a new treatment option for back pain. This therapy alleviates pain by blocking sensory-nerve fibers that pass through the skin along the back. Tiny needles are used to inject a therapeutic solution over the back musculature. Significant improvement can be seen within in one to two weeks after the first treatment, though some horses require a second treatment, two weeks after the first, for full effect. Mesotherapy has been used in France for many years but has only recently been introduced in the U.S.