There is no need to worry about the toxicity of traditional Chinese medicine, as the time-honored therapy is backed by developed theories and drug- making techniques, a leading expert said on Tuesday.

Zhou Chaofan, a researcher with the China Academy of Chinese Medical Sciences, made the remarks in an interview with Xinhua after Australian researchers claimed they had found toxins, allergens and elements of endangered animals in some TCM products.

Scientists at Australia's Murdoch University said the substances were discovered in DNA sequencing tests conducted on 15 TCM products seized by Australian border authorities, according to a story published by the New Zealand Herald last week.

"Some of the TCMs contained plants of the genus Ephedra and Asarum. These plants contain chemicals that can be toxic if the wrong dosage is taken, but none of them actually listed concentrations on the packing," the story quoted lead researcher Michael Bunce as saying.

Zhou said that through more than 2,000 years of practice, TCM has developed its own theories.

"Take Asarum and Ephedra for example," he said. "There has been a long history of using the two herbs."

Guided by developed theories and using proper processing and drug-matching techniques, doctors can enhance TCM's efficacy and resolve the toxicity, he said.

"In 50 years of clinical service, I've prescribed the two herbs thousands of times and they have never caused any problems," Zhou said.

He argued that all medicines are somewhat toxic, but if toxic ingredients are used properly, their efficacy can be improved and their toxicity diminished.

Moreover, Zhou stressed the role of TCM doctors, saying TCM prescriptions are tailor-made to suit patients, so doctors should learn about a patient's health status carefully, prescribe medicines accordingly and advise patients on how to take medicines.

Qian Zhongzhi, an expert with the Chinese Pharmacopoeia Commission, said that unlike most foreign countries where TCM is administered as a dietary or nutritional supplement, China regulates TCM as medicines.

"China's pharmacopoeia provides that only the underground part of Asarum can be used, because the herb's toxins are found in the stem, not the root," Qian said.