When you see dark circular bruises on a Chinese person's neck, back or shoulders, that sight can be quite alarming to the initiated, it's not a sign of a beating, but of traditional Chinese medicine at work.

The bruises are left by cupping therapy, huo guan (literally "fire cupping"), which can relieve pain caused by blocked energy and blood. It can also treat ailments like indigestion, coughing and insomnia.

A cup, usually 3 to 5 centimeters in diameter, is applied to the skin and the pressure in the cup is reduced, creating a vacuum and thus drawing the skin and muscle into the cup.

The vacuum is created either by heating (putting a piece of burning paper inside) or by suctioning out air. The cup or cups usually remain in place for 15 minutes. The heat and vacuum are said to draw out "pathogenic" cold and damp.

Cupping is usually applied to the back of the body on acupuncture points, or where pain is felt. It leaves subcutaneous bruising just like gua sha (scraping) therapy.

Cupping is said to suck out pathogenic energies, such as cold or damp.

Western medicine explains this as promoting blood circulation, which also can relieve pain and ailments and boost the immune system.

Cupping does leave sore muscles and bruises.

Cupping can also help relieve headache, dizziness, coughing, asthma, indigestion, sleeplessness and stomach ache. In these cases, a professional TCM practitioner is required.

Cupping therapy dates back more than 2,000 years in China, though it was originally used to treat carbuncle and draw out infected matter. Muscles came later. It was called jiao fa (horn therapy) in the TCM classic "Zhou Hou Bei Ji Fang" ("Handbook of Prescriptions for Emergencies") by Ge Hong in Eastern Jin Dynasty (317-420 AD).

Horn cups were applied to the skin.

Simple bamboo cups were used in the Tang Dynasty (618-907 AD) and pottery was used in the Qing Dynasty (1644-1911) because it seals for a better vacuum.

The therapy then got its current name huo guan (fire cupping) because of to a new vacuum method - placing a small burning paper into the cup to consume the oxygen and create a vacuum above an acupuncture point. This is used in cases of dizziness, headache or stomach pain due to pathogenic cold, damp or wind.

Glass jars are widely used today. The practitioner uses a lighted alcohol swab to quickly reduce the air pressure in the cup, then applies it to the skin. Some Chinese families prepare their own set of plastic suction cups with air pumps to such out the air. These can be purchased.

Though the cups with air pumps are much easier to use, TCM doctors warn that patients should make sure the pain is not caused by chronic conditions or diseases, such as strained lumbar muscles. In these cases, cupping does not help, though it does not hurt.

Cupping should not be applied to skin with allergic rashes, wounds, edema or cancer.

It should not be applied to the chest or stomach - it's not for pregnant women. People with very high blood pressure and low blood platelet count are not good candidates for therapy.

Applying oil to the skin before therapy helps protect the skin. Therapy usually lasts 10 to 20 minutes, until the skin turns red or purple.

Drink a lot of water afterward. Don't repeat the therapy for two or three days.

The color of bruises signifies the patient's health. Dark bruises indicate serious blocked blood and energy or a serious pathogenic cold invasion.

The darker, the more serious. Red bruises indicate insufficient yin energy or pathogenic heat inside. Light bruising and bruising that fades quickly indicate good health or very mild ailments.

(Shanghai Daily October 7, 2008)