Once you apply Salonpas patches to the neck and/or to the shoulders, the active ingredients quickly pass through the skin. These ingredients then penetrate into the bloodstream through the capillary vessels, providing fast, effective pain relief where it’s needed most. Salonpas patches act directly and immediately on the areas needing relief without going through the digestive system. For temporary relief of minor aches & pains of muscles and joints associated with simple backache, arthritis, strains, bruises and sprains.