The World Health Organization says adverse drug reactions to traditional or alternative medicines have more than doubled in three years. The WHO warns the unregulated use of these medicines may cause harm or even death.

The World Health Organization says the consumption of traditional medicines is increasing in all countries. WHO Assistant director General Vladimir Lephakin says these medicines are sometimes beneficial, but sometimes cause harm. He says natural does not always mean safe.

"The assumption that traditional medicines, very often so-called natural medicine, is safe is not correct. There are a lot of examples when people suffer and not only suffer, but also die because of drug interaction or non-proper use of traditional medicine," he says.

As the use of traditional or alternative medicines increases, Dr. Lephakin says so do reports of adverse reactions. He notes China reported nearly 10,000 cases of bad reactions to traditional drugs in 2002. This was more than double the number reported in the 1990s.

Dr. Lephakin notes people in developed countries do not have the culture of using traditional medicines as do people in developing countries where up to 80 percent of the population relies on traditional medicine for primary health care.

The WHO expert says what often gets people into trouble is that many traditional and alternative medicine products are sold over the counter and used for self-medication.

Another potential risk he says is that patients often do not inform their doctors they are taking traditional medicines. He says the use of these drugs in combination with conventional medicine can, sometimes, lead to life-threatening situations.

Dr. Lephakin says food supplements are an even more complicated area than traditional medicines. In most countries, he says, they are not regulated, and therefore there is no guarantee of quality.

"Some studies have shown that in different countries, in food supplements, they found some toxic heavy metals," he says. "And in some, let us say extreme cases, in food supplements, there were some narcotics to make people dependent on this."

Dr. Lephakin says there is a need for strengthening the control of food supplements in all countries. The United States took such a step in December when it warned consumers not to take a popular dietary supplement containing ephedra after several people died. Ephedra is a natural substance used in China to treat coughs.

The WHO official adds vitamins also should be regulated. In the case of vitamins, he says, more is not necessarily better. He warns large intakes of vitamins over a long period of time can be dangerous.