The concentration of lipoprotein (a) in plasma is under stringent genetic control and raised concentrations are strongly linked to coronary heart disease, in particular when low density lipoprotein levels are also increased. We serially monitored serum Lp(a) in 14 hypercholesterolemic patients who were treated with Pravastatin over a period of two years. C-reactive protein levels were also quantified to exclude a possible 'acute-phase' response as a reason for a sudden increase in the Lp(a) concentration. No significant changes were seen in mean Lp(a) levels after 24 months of therapy. Considerable fluctuations of serum Lp(a) levels occurred during the course of treatment. These were in some cases associated with raised C-reactive protein concentrations and might therefore be attributable to an 'acute-phase' response. We conclude that the HMG-CoA reductase inhibitor Pravastatin has no long-lasting effects on Lp(a) levels in hypercholesterolemic patients suffering from coronary heart disease.