Doctors and pharmacists have warned against taking health supplements that supposedly help reduce the harmful effects of smoking and drinking. They are worried that some may be misled into overindulging. Manufacturers of one product, a green tea extract, claim it can help those exposed to tobacco smoke, air pollution and exhaust fumes by strengthening their lungs and immune system. The supplement has been on sale for several months, backed by newspaper and television promotions. TV adverts for another product, a dietary fibre, say it absorbs alcohol in the stomach and reduces the amount that enters blood vessels. Dealers selling the products in Hong Kong have acknowledged that clinical tests have not yet proved their effectiveness. Phyllis Poon, marketing manager of the company that sells anti-smoke supplements, admitted that clinical tests conducted in the US were not 'good enough'. After the company consulted local doctors, it withdrew claims in latest promotions last month that the product could reduce levels of cancer-causing substances. But she insisted the product could protect people from air pollution and smoking because of its healthy organic ingredients. 'We are not encouraging people to smoke. We just want to help smokers who face difficulties in quitting to keep better health,' Ms Poon said. Robert Lee, director of the firm that sells anti-alcohol pills, admitted the supplement could not prevent people getting drunk and that it was not meant to encourage excessive drinking. He said it was developed and produced in Hong Kong, and that the developer conducted clinical tests only on mice. Both Ms Poon and Mr Lee said the health supplements were food products, not pharmaceuticals, so they were not required by law to register. A Health Department spokeswoman said it 'is not aware of any scientific evidence showing the efficacy of the active ingredients of the products in reducing the risk and harmful effects from smoking and excessive drinking of alcohol'. It also pointed out that smoking and alcohol misuse were closely related to many non-communicable diseases, such as cancer and lung, heart and liver diseases. A medical professor at the University of Hong Kong, Kenneth Tsang Wah-tak, said he had never heard of any supplement proven to relieve the side effects of smoking. 'The only way to get rid of the side effects is not to smoke at all,' Professor Tsang said. 'I am extremely worried that people may overlook the risk of smoking.' Another professor at the university, Lai Ching-lung, said he did not know of any supplement that could protect the liver from the effects of too much alcohol. 'An appropriate amount of alcohol can be good for health, but those who have liver illnesses should avoid drinking,' he said. William Chui Chun-ming, education director of the Society of Hospital Pharmacists, said many supplements lacked scientific support for claims to prevent diseases. A spokeswoman for the Consumer Council suggested people consult their doctors before taking health supplements.