Bacterial infections are common complications in decompensated cirrhosis, but their relationship with hemostasis has not been studied. We prospectively assessed whether infection affects hemostasis in cirrhosis using routine hemostasis tests and thrombelastography (TEG), a global test of hemostatic function. Eighty-four cirrhotic patients (Child-Pugh B: 26; C: 58) without overt bleeding or blood-product transfusion were prospectively evaluated with routine hemostasis tests and TEG on admission and/or the first day with signs of infection and 5 days later. There were 30 patients with infection; 15 had infection on admission, and 15 developed infection in hospital. In the patients who developed infection in hospital, there was a significant deterioration in all routine hemostasis tests except platelet count (PLT) and in all TEG parameters, on the first day of infection compared with 7 +/- 3 days previously. The same parameters significantly improved from the first day of infection to day 5 and after (P <.02) only in the 22 patients whose infection resolved, while the r, k, and alpha TEG parameters significantly worsened in the 8 patients with persistent infection. In those who developed infection in hospital and were cured (n = 11), the 5-day parameters did not differ from their preinfection values. In conclusion, bacterial infections frequently impair hemostasis in decompensated cirrhotic patients. Successful treatment of infection usually restores hemostasis parameters to preinfection levels in 5 days. Thus, infection may have a role in the bleeding diathesis of cirrhosis.