This study was designed to evaluate major fibrinolytic parameters in relation to parameters of inflammation associated with different kinds of pleural effusion. Sixty patients with pleural effusion were studied. The underlying aetiology was empyema in 10 cases, tuberculosis in 9, cancer in 31, cardiac failure in 7, and undetermined in 3. Plasminogen, plasminogen activator inhibitor 1 (PAI-1) and 2 (PAI-2), tissue type plasminogen activator (t-PA), urokinase (u-PA) and D-dimers (D-D) were quantified in plasma samples and pleural effusion specimens. These data were then correlated with inflammatory or infectious parameters, i.e. fibrinogen, von Willebrand factor (vWF), erythrocyte sedimentation rate (ESR), protein concentration, and white blood cell count. D-D levels were higher in pleural fluid than in plasma. D-D levels were not correlated with either plasminogen activator or plasminogen activator inhibitor levels, suggesting the presence of other fibrinolytic pathways. PAI levels (PAI activity, PAI-1 antigenicity, PAI-2 antigenicity) and vWF levels were significantly higher in patients with tuberculosis and empyema than in patients with cancer or cardiac failure. Regression analysis between inflammatory and fibrinolytic parameters showed that pleural PAI levels were significantly correlated with pleural neutrophil count, vWF levels, and plasma fibrinogen levels. D-D levels were correlated with blood ESR. No significant difference in pleural t-PA, u-PA and D-D levels was observed between aetiologies. The highest pleural t-PA and u-PA values were noted in patients with cancer, especially lymphoma. Plasma t-PA levels were higher inpatients with pleural effusion secondary to congestive heart failure, but this difference did not reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)