Acupuncture has been used for thousands of years to treat disease. From a Traditional Chinese Medicine perspective, the body has several rivers of energy (qi), called meridians. When the qi is balanced and free-flowing, the person is healthy. Depleted or blocked qi cause pain or illness. Acupuncture can restore the balance of qi. From a western medical viewpoint, acupuncture stimulates the body's production of endorphins and immune response.
Acupuncture can also help your pets. If you doubt the effectiveness of acupuncture or think it is a placebo, do a search for pet acupuncture videos. I included a couple here. The set-up in China is pretty elaborate! Japanese acupuncture tends to be the gentlest, then Chinese, then Korean. That seems to be true for the dogs, too. :)