Presence of bacterial DNA in noninfected patients with cirrhosis and ascites is associated with a marked inflammatory response including activation of the inducible form of nitric oxide synthase and release of nitric oxide, similar to that observed in patients with spontaneous bacterial peritonitis. Although presence of bacterial DNA is associated with an impaired prognosis, no information is available regarding its hemodynamic consequences. Systemic and hepatic hemodynamics before and after a liquid test meal were assessed in a series of 75 noninfected patients with cirrhosis (55 with ascites). Bacterial DNA was measured by polymerase chain reaction. Bacterial DNA was detected only in patients with ascites. Clinical data and liver function were similar in ascitic patients with presence (n = 21) or absence of bacterial DNA (n = 34). Bacterial-DNA(+) patients had significantly lower mean arterial pressure (P = 0.002) and systemic vascular resistance (P = 0.03) than bacterial-DNA(−) patients. Cardiac output, cardiopulmonary pressures, hepatic venous pressure gradient (HVPG), and hepatic blood flow were similar in both groups. Thirty minutes after the test meal, in response to increased blood flow caused by postprandial hyperemia, there was a significantly greater increase in HVPG and impaired hepatic vasorelaxation in bacterial-DNA(+) as compared with bacterial-DNA(−) patients, which indicates hepatic endothelial dysfunction. Indeed, the increase in HVPG after the test meal significantly correlated with serum bacterial DNA concentration. Conclusion: Presence of bacterial DNA, a marker of bacterial translocation, is associated with aggravation of peripheral vasodilation and with worsening of intrahepatic endothelial dysfunction. (HEPATOLOGY 2010;.)