Objective To measure the concentration of D-dimer (DD), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) and plasminogen (PLG) activity in plasma and cerebrospinal fluid in patients with acute cerebral infarction and to investigate their clinical significance. Methods The concentrations of D-dimer, t-PA, and PAI-1 in plasma and cerebrospinal fluid in patients were measured by enzyme-linked immunosorbent assay (ELISA). The PLG biological activity was detected using the chromophore method. The results were compared with those of the controls. Results The concentrations of D-dimer, t-PA and PAI-1 in cerebrospinal fluid and plasma in patients with acute cerebral infarction were much higher than those of normal subjects ( P <0.01). Conversely, the level of PLG activity was significantly lower in the patients than in the controls ( P <0.01).Conclusion Hypercoagulability and secondary hyperfibrinolysis exist in patients with acute cerebral infarction. Objective To measure the concentration of D-dimer (DD), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) and plasminogen (PLG) activity in plasma and cerebrospinal fluid in patients with acute cerebral infarction Methods for concentrations of D-dimer, t-PA, and PAI-1 in plasma and cerebrospinal fluid in patients were measured by enzyme-linked immunosorbent assay (ELISA). The PLG biological activity was detected using the chromophore Results The concentrations were compared with those of the controls. Results The concentrations of D-dimer, t-PA and PAI-1 in cerebrospinal fluid and plasma in patients with acute cerebral infarction were much higher than those of normal subjects (P <0.01 ) Conversely, the level of PLG activity was significantly lower in the patients than in the controls (P <0.01). Conclusions Hypercoagulability and secondary hyperfibrinolysis exist in patients with acute cerebral infarction.