AIM:To investigate the therapeutic effect of umbilical cordblood transplantation(UCBT)on patients with severe viralhepatitis and on liver lesions in rats.METHODS:One hundred and fifty three patients with severeviral hepatitis were included in the study between April 1990and July 2002.The patients were treated with adult plasmatransfusion(control),UCBT,plasma exchange(PE)and UCBTcombined with PE(UCBT+PE)respectively.The therapeuticeffectiveness was evaluated by serial determinations of liverfunction,lipids and immune function in all patients beforeand after the treatment.The model of experimental hepaticfailure was constructed in SD rats by injecting carbontetrachloride.Then,the rats were given normal saline,adultplasma or neonate cord blood intraperitoneally.After detectionof liver function,the rats were killed and morphologicalchanges of the liver were microscopically observed.RESULTS:UCBT group and UCBT+PE group had muchbetter improvement in liver and immune functions thancontrol group and PE group.The patients in UCBT+PE grouphad the best clinical efficacy.UCBT was safe and had noside effects.The animal experiment showed significantimprovements in liver function and survival rate in neonatecord blood group as compared with adult plasma group.The histopathology of rat’s liver indicated that neonate cordblood application could decrease the liver injury and increasehepatocellular regeneration.CONCLUSION:UCBT demonstrated a good therapeuticeffect on severe viral hepatitis and no obvious side effects.Umbilical cord blood can attenuate the liver lesions andreproduce hepatocyte.The treatment of UCBT combinedwith PE was much better than that of single plasmaexchange,thus UCBT can enhance the therapeutic effect ofplasma exchange on severe viral hepatitis. To investigate the therapeutic effect of umbilical cordblood transplantation (UCBT) on patients with severe viral hepatitis and on liver lesions in rats. METHODS: One hundred and fifty three patients with severe viral hepatitis were included in the study between April 1990 and July 2002. were treated with adult plasma transfusion (control), UCBT, plasma exchange (PE) and UCBT combined with PE (UCBT + PE) respectively.The therapeutice effect was was evaluated by serial determinations of liver function, lipids and immune function in all patients before and after the treatment. model of experimental hepatic capsule was constructed in SD rats by injecting carbon tetrachloride. Chen, the rats were given normal saline, adult placenta or neonate cord blood intraperitoneally. After detection of liver function, the rats were killed and morphological changes of the liver were microscopically observed .RESULTS: UCBT group and UCBT + PE group had muchbetter improvement in liver and immune functions thancontrol gro up and PE group. The patients in UCBT + PE grouphad the best clinical efficacy. UCBT was safe and had noside effects. The animal experiment showed significantmprovements in liver function and survival rate in neonatecord blood group as compared with adult plasma group. The histopathology of rat’s liver indicated that neonate cordblood application could decrease the liver injury and increase hepatocellular regeneration. CONCLUSION: UCBT demonstrated a good therapeuticeffect on severe viral hepatitis and no obvious side effects. Umbilical cord blood can attenuate the liver lesions and regeneration hepatocyte. The treatment of UCBT combined with PE was much better than that of single plasma exchange, thus UCBT can enhance the therapeutic effect of plasma exchange on severe viral hepatitis.