Swine flu, or more accurately A-H1N1 flu, has alerted people around the world and in China where many people take anti-viral medication to prevent catching flu.

But anti-viral medicine is ineffective since flu strains mutate, and it can also be detrimental to health by building resistance, according to a doctor of traditional Chinese medicine.

TCM practitioners urge people to take the standard precautions - primarily frequent hand washing, airing of rooms. If you feel sick, see a doctor.

TCM regards and treats ailments as energy imbalances. It does not have a "germ theory of disease" but perceives pathogens as environmental factors such as pathogenic heat, cold, wind and damp.

Improving one's healthy energy (qi) and boosting immunity can help defending against the flu, according Dr Wu Yingen, a member of the Shanghai Expert Panel on Preventing and Controlling A-H1N1 flu. He is the chief physician of Longhua Hospital attached to Shanghai University of TCM.

The ordinary flu virus usually attacks the respiratory system or digestive system, but A-H1N1 can attack one or both, says Dr Wu.

Although it is highly contagious - the virus can survive for up to 48 hours on surfaces - it is generally not fatal and is often mild. Patients exhibit some of the usual flu symptoms, including coughing, sore throat, headache, fever, weakness, muscle aches, diarrhea and vomiting.

A few patients develop very high fever (39 degrees Celsius or above), pneumonia, kidney failure or septicemia, which can be fatal.

Dr Wu advises those with symptoms to see a doctor right away, avoid public places, and wear a mask.

"The flu is likely caused by invasion of pathogenic heat, pathogenic cold and pathogenic dampness, according to its different symptoms," says Dr Wu.

Sore throat and fever suggest pathogenic heat, aches and pains suggest pathogenic cold, while diarrhea and stomach ache indicate pathogenic damp, he says.

Dispelling the pathogenic energies while strengthening healthy energy is the strategy agreed upon by the panel to treat A-H1N1, he says.

To treat patients with respiratory symptoms, herbs like jiu ma huang (Chinese ephedra) and chai hu (Chinese thorowax) are recommended. There are also effective Chinese patent drugs including Banlangen chongji (radix isatidis medicinal granules), Shuanghuanglian (oral liquid composed of honeysuckle, baikal skullcap root and forsythia), and Zheng chaihu yin keli (Chinese thorowax granules).

To relieve digestive system symptoms, TCM recommends herbs like ge gen (radix puerariae) and ageratum. People can take patent drugs such as Huoxiang zhengqi zhiji (ageratum oral liquid) and Gegen qinlian (pills composed of radix puerariae, baikal skullcap root, coptis root and liquorice).

For those with high fever, chest congestion, irritability and breathing problems, TCM recommends patent drugs like Qingkailing pills and Angong niuhuang wan, mainly composed of herbs like cow-bezoar, cornu bubali, musk and baikal skullcap root.

These medicines are effective in treating other kinds of flu, according to Dr Wu. They only treat symptoms, however, and do not prevent people from catching flu.

Though A-H1N1 is highly infections, people in China don't need to worry too much at this time, says Dr Wu.

"There are two peaks of annual flu attacks in China, one in January and February while the other in August and September," says Dr Wu. "We are now in a low season and the flu has been controlled well so far."

To prevent A-H1N1 flu, some people turn to medicines like anti-viral oral liquid, even though they are completely healthy. But this is unnecessary and unhelpful because it doesn't work and extensive self-dosing can cause drug-resistance and make future treatment difficult.

TCM drugs like radix isatidis medicinal granules can help relieve symptoms, but don't prevent this new flu or other flus, says Dr Wu.

"You cannot prevent catching flu by taking anti-viral medication as the flu virus mutates so quickly," says Dr Wu. Medication must be specific to the virus.

"Strengthening your healthy energy, in other words, improving your immunity can help fight the invasion of pathogenic energies that cause flu."

The six-herb-prescription used in combating SARS is recommended for high- risk groups, including staff in hospitals, hotels, airports and other congested public places. It is comprised of huang qi (milk veteh), bai shu (atractylodes macrocephaia), fang feng (divaricate saposhnikovia root), guan zhong (rhizome of cyrtomium), honeysuckle and dried orange peel.

The first three herbs can help strengthen healthy and defensive energy, while the other three herbs can help prevent and control a virus. Dried orange peel can also aid the digestive system. Chinese patent drug Yu pinfeng san composed of huang qi, bai shu and fang feng also works.

As for ordinary citizens, having enough sleep, eating a balanced and nutritious diet and taking regular exercise is enough to improve immunity. Frequent hand washing and airing rooms are always important in prevention.

Though vitamins, such as C, can help improve immunity if taken regularly in moderation, taking too much can cause stomach acid and other problems. It's best to get vitamins from food, not nutritional supplements.