The findings of a study of scientists at Stony Brook University in New York (USA) recently announced reaffirmed some Chinese herbal manufacturing is widely used in Taiwan have contained aristolochic acid (AA) - a cancer causing toxin most powerful in a number of medicinal plants.

The study based on 151 patients with urinary tract cancer, of which 60% was found to have mutations worsen when patients are taking herbs containing AA.

The previous study also said more than one third of Taiwan's population has used herbs containing AA and the rate of cancer of the kidney and urinary tract cancer in this area is the world's highest, more than four times higher than in Western countries rarely use herbs.