A Hong Kong watchdog has warned consumers that prolonged or excessive use of certain herbal dietary products can be dangerous to their health. The Hong Kong Consumer Council said on Thursday that 22 of 36 herbal slimming pills and detoxifying treatments they tested contained anthraquinone, a naturally occurring laxative found in plants such as rhubarb and aloe. Traditional Chinese doctors say users could become dependent on the drug and may become seriously constipated when they stop taking the diet products. "It should only be used occasionally because prolonged use can disrupt the normal functioning of the intestines," Li Ning-hon, a Chinese medicine doctor, told Reuters on Friday. The tests also found that four of the 22 products did not accurately label their ingredients, while others failed to warn users of potential side effects and even claimed to have no adverse side effects. "The Chinese and English lists of ingredients were different and so were the ingredient lists on the box and the insert," said the council. In one case even the recommended dosage was not the same in English and Chinese. The tests, carried out jointly by the Consumer Council and the Hong Kong Institute of Chinese Medicine, showed that "Selfit," imported from China, and the locally manufactured "Beauty & Health" carried the highest concentrations of the drug. The Hong Kong government is currently examining ways to regulate traditional Chinese medicinal products, but at present there are no laws specifically regulating their use. Diet pills and powders have become hugely popular in Hong Kong where most women associate beauty with being slim, and a wide selection of Chinese herbal diet products are available without prescription at most local chemists.