@@ To study the relationship ofplasma ammonia and station of liver，renal，gastrointestinal tract，and to research the mechanism of plasma ammonia elevated in patients with cirrhosis，to define the affections and indiVidual method of lowering ammonia.The study population enrolled 2743 patients who had liver dysfunction,Pathology groups were 1 00 patients who had just cirrhosis，100 patiems who had hepatorenal syndrome，and 95 patiems who had hepatointestinal syndrome. Pathology control groups were 80 patients who had just renal dysfunction，1 1 3 patients who had just gastrointestinal hemorrhage，50 patients who had just intestinal obstruction.Normal control group was 80 healthy people.Collected the serum and plasma samples of enrolled subjects，and measured the carbamoyl phosphate synthetase Ⅰ(CPS Ⅰ)，ornithine carbamoyl transferase(OCT)，liver function indicators，and ammonia.Analyze difference of ammonia among patients who had liver dysfunction.To analyze difference of ammonia，CPS I，OCT among patients who had cirrhosis and who did not，and correlation of CPS Ⅰ，OCT with ammonia.To compare ammonia among patients who had HRS and renal dysfunction with normal controls，and analyze the correlation of serum urea，creatinine with ammonia among 40 patients.