A recent Beantown count of liver tests delivered bad news: HAART can cause severe toxicity. Raymond Chung, MD, of Mass General Hospital, evaluated data from more than 10,000 HIVers between 1991 and 2000. Serious liver toxicity developed in about 10 percent; of these, almost one-quarter had to go off therapy. And more than one-half manifested after half a year of treatment. "You're not out of the woods because you get through six months," Chung said. "Continual testing is a must."