Patients with HIV infection who started cholesterol treatments had smaller changes in LDL cholesterol than patients without HIV infection; this did not vary with type of HIV treatment. High triglyceride levels were more difficult to treat in HIV-infected patients than in uninfected patients, and the difficulty varied with the type of HIV treatment. Patients receiving regimens containing both protease inhibitors and NNRTIs had the smallest changes in triglyceride levels, followed by patients receiving protease inhibitors only. However, HIV-infected patients who were receiving NNRTIs only and the cholesterol-lowering drug gemfibrozil had decreases in triglyceride levels similar to those in uninfected patients receiving gemfibrozil. Side effects of cholesterol treatments occurred in very few patients, but HIV-infected patients had more changes in liver and muscle enzyme levels than uninfected patients.