Serum lipids and lipoprotein patterns were prospectively analyzed in 33 previously untreated patients with active chronic inflammatory arthritides during different anti-inflammatory and disease-modifying drug regimens. Before treatment the lipoprotein pattern was characterized by low cholesterol concentrations in all lipoprotein fractions and low triglyceride concentrations in the very-low-density lipoprotein fraction as well as in the high-density lipoprotein fraction. During treatment with prednisolone combined with azathioprine or cyclophosphamide (n = 10), a reduction of the disease activity was achieved and the lipoprotein pattern was normalized; similar results were noted in a small group of patients (n = 4) treated with prednisolone alone while nonsteroidal anti-inflammatory drug therapy (n = 9) neither significantly affected the lipoprotein pattern nor the inflammatory activity measured by the acute-phase reactants. The long-term treatment with penicillamine (n = 4) and chloroquine (n = 6) induced both a clinical remission of the disease and a reduction of the inflammatory activity. The lipoprotein concentrations started to reverse to the normal values during penicillamine treatment. In contrast, in the chloroquine-treated group the alterations in lipoprotein lipid concentrations were further pronounced, ie, the cholesterol and triglyceride concentrations in serum and the very-low-density lipoprotein fraction decreased.