Statins can lower the circulating levels of C reactive protein (CRP). This effect may be relevant because CRP is a predictor of vascular risk. In contrast, the evidence that fibrates lower CRP levels is very limited. The effect of treatment with ciprofibrate (100 mg once daily) was investigated for 8 weeks in 30 patients with primary dyslipidemia. There was a significant (p < 0.01) decrease in median (range) CRP levels by 36.8% from 1.9 mg/L (1.0-6.0 mg/L) to 1.2 mg/L (1.0-5.5 mg/L). Plasma fibrinogen levels were also significantly (p = 0.05) reduced. There was no correlation between the fall in CRP levels and the changes in lipid or fibrinogen levels. These findings support the concept that fibrates, like the statins, lower serum CRP levels. However, fibrates have a different mode of action. Fibrates (with the exception of gemfibrozil) also consistently lower plasma fibrinogen levels. In contrast, the effect of statins on the circulating levels of this coagulation factor remains to be defined. These differences may help in defining the mechanisms responsible for drug-induced changes in the circulating levels of CRP and fibrinogen. A favorable effect on CRP and fibrinogen levels may increase the clinical efficacy of statins and fibrates.