TRIALS on ulcer patients carried out by Chinese University researchers at the Prince of Wales Hospital have led to a breakthrough in the treatment of duodenal ulcers. The findings prove that ulcers, which affect about 10 per cent of people in Hong Kong, can be healed using antibiotics rather than traditional, far more expensive anti-ulcer drugs. The research, which was published in The Lancet, is set to radically alter medical thinking regarding the cause and treatment of duodenal ulcers while drastically cutting Hong Kong's drug bill. Professor Arthur Li Kwok-cheung, the dean of medicine at the Chinese University, said: ''We now have firm evidence that if we use antibiotics to treat ulcers they go away.'' For the past 70 years, the treatment of duodenal ulcers has relied on cutting the level of gastric acid, although the ulcer often re-appears after healing. Although the use of antibiotics has already been shown to drastically reduce the likelihood of the ulcer recurring, the findings shed important new light on the cause of the disease. The results of the research will soon be broadcast to 150 million people worldwide after the BBC World Service approached the university and made a documentary. To find out if antibiotics could heal ulcers, 153 patients with bacterial infection and duodenal ulcers took part in trials at the Prince of Wales Hospital. Half of them were given a one-week course of three antibiotics while the other half were given an antacid for four weeks and the three antibiotics for the first week. Four weeks after treatment, 132 patients were analysed and it was found that the ulcers healed in 60 of those who had taken only the three antibiotics and 63 who had also taken the antacid. The bacteria was eradicated in 61 of those who had received just the antibiotics and 66 who had also received the antacid, although symptoms were reduced more effectively in patients who took the antacid. However, although combining antacid with antibiotic therapy helped in terms of pain relief, the antacid had no additional effect on ulcer healing, the research showed. Prof. Li said: ''The results are not conclusive and more research is still needed, but we believe we have gone some way to proving that duodenal ulcers are caused by a bacteria rather than too much acid.'' Duodenal ulcers are far more common in Chinese communities than in the West and so the university now plans to look at whether cross-infection of the bacteria among families is at the root of the problem.