Cupping is a TCM therapy involving the placement of glass, plastic, or bamboo cups on the skin with a vacuum. The therapy is used to relieve what is called "stagnation" in TCM terms, and is used in the treatment of respiratory diseases such as the common cold, pneumonia, and bronchitis. Cupping is also used to treat back, neck, shoulder, and other musculoskeletal pain. Its advocates claim it has other applications as well.