A widely available medicine appears to significantly protect alcoholics from fatal liver disease, even when they continue to drink moderately, a study has found. The drug propylthiouracil or PTU cut the death rate in half among alcoholics who took it over two years, and it was almost completely effective among those who drank the least. Experts cautioned PTU does not allow people to drink heavily, and the best way to avoid liver disease is to give up alcohol. Ordinarily, PTU is used to treat overactive thyroid glands. The study, by researchers at the Addiction Research Foundation in Toronto, Canada, was published in today's New England Journal of Medicine.