Lactic acidosis has been associated with AZT, ddI and d4T therapy.6,7,8,9,10,11,12,13,14 Fortgang and associates15 estimated that the incidence of NRTI-associated lactic acidosis was 1.3 per 1000 person-years. However, these researchers reviewed patients who had each been treated with a single antiretroviral agent, and their results may underestimate the incidence of NRTI-associated lactic acidosis in the current era of triple therapy. Given its potential lethality, awareness of the signs and symptoms of NRTI-associated lactic acidosis (Box 1) is important in the management of HIV- infected patients. The clinical course is characterized by often vague complaints of malaise, nausea and vomiting, fatigue and tachypnea,16 followed by liver failure, cardiac dysrhythmias and death.