In this ancient Chinese technique, bell-shaped vessels (now made of glass) with a volume of approximately 4 ounces are inverted over the skin. The modern use of glass enables the practitioner to see the skin and monitor what is happening.
One of several techniques may be used to create low pressure inside the cup: for example, a flash fire, which consumes all the oxygen and creates a vacuum before going out. The very hot air inside the vessel cools rapidly when placed against the skin. The reduced pressure within the cups draws the skin up into it.
Typically, a series of vessels are used in the area to be treated. In the most common form, a series of 8 to 12 are placed along the back in two rows, the spine separating the rows, and left there for an average of 20 minutes. It leaves distinctive circular marks when done properly. The areas may feel as if they were sunburned for a short while. Ancient Chinese medicine prescribes this technique in cases where “stagnation” must be treated, commonly in the lungs, when it is used to treat coughs, and tightness or congestion in the chest.
It draws stagnant qi from deep within to the surface to be released, so easing pain. It is also sometimes used to treat musculoskeletal pain. Often, it is used in conjunction with other techniques, like acupuncture and acupressure. This method is applied to acupuncture points on the body where there is pain (stagnation). Some massage oil is often first applied to the skin to allow the glass vessels to slide when they have been positioned. This technique is known as gliding.
An easy way to visualize what this does is to picture the flow of energy in your body as like plumbing. Sometimes directly manipulating the pipes with pressure works to eliminate blockages. But other times, you need to take a plunger to the problem, using negative pressure to pull things out.
In addition to treating the stagnation-based illnesses, cupping has been reported to leave a long-term feeling of relaxation and invigoration. It does not harm you when performed by someone properly trained in the technique, and is perfectly safe to use in conjunction with other more mainstream forms of medicine. It is very popular in China and has a long history of use in acupuncture practice.