AIM: To evaluate the effect of oral intake of branched-chain amino acids (BCAA) on brain perfusion in patients with liver cirrhosis. METHODS: Single photon emission computed tomography scans were performed in 43 patients with cirrhosis and in 15 age-matched healthy subjects. Twenty-nine out of forty-three patients were randomly treated with either BCAA granules or placebo, and single photon emission computed tomography was performed before and after the treatment. We measured the regional cerebral blood flow values using a three-dimensional stereotaxic region of interest template. RESULTS: Cirrhotic patients had regions of significant hypoperfusion in the bilateral central (right P=0.039, P＜0.05; left P = 0.006 P＜0.01), parietal (right P = 0.018, P＜0.05; left P = 0.009, P＜0.01), angular (right P = 0.039, P＜0.05; left P = 0.008, P＜0.01), and left pericallosal segments (P = 0.038 P＜0.05) as compared with healthy subjects. A significant increase in cerebral perfusion was observed 70 min after the oral intake of BCAA in the angular (right P = 0.012, P＜0.05; left P = 0.049, P＜0.05), temporal (right P=0.012, P＜0.05; left P=0.038, P＜0.05), pericallosal segments (right P=0.025, P＜0.05; left P=0.049, P＜0.05) and left precentral (P = 0.044, P＜0.05), parietal (P = 0.040, P＜0.05) and thalamus (P = 0.033, P＜0.05). No significant change in perfusion was observed in the placebo group. CONCLUSION: Administration of BCAA rapidly improves cerebral perfusion. AIM: To evaluate the effect of oral intake of branched-chain amino acids (BCAA) on brain perfusion in patients with liver cirrhosis. METHODS: Single photon emission computed tomography were performed in 43 patients with cirrhosis and in 15 age-matched healthy subjects Weighted the regional cerebral blood flow values ​​using a three-dimensional stereotaxic region of interest template. RESULTS: Cirrhotic patients had regions of significant hypoperfusion in the bilateral central (right P = 0.039, P <0.05; left P = 0.006 P <0.01) , P <0.01), angular (P = 0.039, P <0.05; P = 0.008, P <0.01), and left pericallosal segments perfusion was obs erved 70 min after the oral intake of BCAA in the angular (right P = 0.012, P <0.05; left P = 0.049, P <0.05) (P = 0.044, P <0.05), parietal (P = 0.040, P <0.05) and thalamus (P <0.05) P = 0.033, P <0.05). No significant change in perfusion was observed in the placebo group. CONCLUSION: Administration of BCAA Rapid improves cerebral perfusion.