AIM:To observe the therapeutic efficacy of high-doseVitamin C (Vit.C) on acute pancreatitis (AP),and to exploreits potential mechanisms.METHODS:Eghty-four AP patients were divided intotreatment group and control group,40 healthy subjectswere taken as a normal group.In the treatment group,Vit.C (10 g/day) was given intravenously for 5 days,whereas in the control group,Vit.C (1 g/day) was givenintravenously for 5 days.Symptoms,physical signs,durationof hospitalization,complications and mortality rate weremonitored.Meanwhile,serum amylase,urine amylase andleukocyte counts were also determined.The concentrationof plasma vitamin C (P-VC),plasma lipid peroxide (P-LPO),plasma vitamin E (P-VE),plasma β-carotene (P-β-CAR),whole blood glutathione (WB-GSH) and the activity oferythrocyte surperoxide dimutase (E-SOD) and erythrocytecatalase (E-CAT) as well as T lymphocyte phenotype weremeasured by spectrophotometry in the normal group andbefore and after treatment with Vit.C in the treatmentand the control group.RESULTS:Compared with the normal group,the averagevalues of P-VC,P-VE,P-β-CAR,WB-GSH and the activityof E-SOD and E-CAT in AP patients were significantlydecreased and the average value of P-LPO was significantlyincreased,especially in severe acute pancreatitis (SAP)patients (P<0.05.P-VC,P=0.045;P-VE,P=0.038;P=0.041;P-β-CAR,P =0.046;WB-GSH,P =0.039;E-SOD,P=0.019;E-CAT,P =0.020;P-LPO,P =0.038).Compared with thenormal group,CD_3 and CD_4 positive cells in AP patientswere significantly decreased.The ratio of CD_4/CD_8 and CD_4positive cells were decreased,especially in SAP patients(P<0.05.CD_4/CD_8,P =0.041;CD_4,P =0.019).Fever andvomiting disappeared,and leukocyte counts and amylasein urine and blood become normal quicker in the treatmentgroup than in the control group.Moreover,patients intreatment group also had a higher cure rate,a lowercomplication rate and a shorter in-ward days comparedwith those in he control group.After treatment,the averagevalue of P-VC was significantly higher and the values ofSIL-2R,TNF-α,IL-6 and IL-8 were significantly lower in thetreatment group than in the control group (P<0.05 P-VC, P=0.045;SIL-2R,P=0.012;TNF-α,P=0.030;IL-6,P=0.015;and IL-8,P =0.043).In addition,the ratio of CD_4/CD_8 andCD4 positive cells in the patients of treatment group weresignificantly higher than that of the control group aftertreatment (P<0.05.CD_4/CD_8,P =0.039;CD_4,P =0.024).CONCLUSION:High-dose vitamin C has therapeutic efficacyon acute pancreatitis.The potential mechanisms includepromotion of anti-oxidizing ability of AP patients,blockingof lipid peroxidation in the plasma and improvement ofcellular immune function. AIM: To observe the therapeutic efficacy of high-dose Vitamin C (Vit. C) on acute pancreatitis (AP), and to explore the potential mechanisms. METHODS: Eghty-four AP patients were divided intotreatment group and control group, 40 healthy subjectswere taken as A normal group. The treatment group, Vit. C (10 g / day) was given intravenously for 5 days, while in the control group, Vit. C (1 g / day) was givenintravenously for 5 days.Symptoms, physical signs duration of hospitalization, complications and mortality rate were monitored. Meanwhile, serum amylase, urine amylase and leukocyte counts were also determined. This concentration of plasma vitamin C (P-VC), plasma lipid peroxide (P-LPO) (β-CAR), whole blood glutathione (WB-GSH) and the activity of erythrocyte surperoxide dimutase (E-SOD) and erythrocytecatalase (E-CAT) as well as T lymphocyte phenotype weremeasured by spectrophotometry in the normal group and before and after treatment with Vit. C in the treatment and t he control group .RESULTS: Compared with the normal group, the averagevalues ​​of P-VC, P-VE, P-β-CAR, WB-GSH and the activityof E-SOD and E-CAT in AP patients were significantlycreased and the average P of P-LPO was significantly increased, especially in severe acute pancreatitis (SAP) patients (P <0.05.P-VC, P = 0.045; P-VE, E-SOD, P = 0.019; E-CAT, P = 0.020; P-LPO, P = 0.038) .Compared with normal group, CD_3 and CD_4 positive cells in AP patientswere significantly decreased .The ratio of CD_4 / CD_8 and CD_4 positive cells were decreased, especially in SAP patients (P <0.05.CD_4 / CD_8, P = 0.041; CD_4, P = 0.019) .Fever and vomiting disappeared, and leukocyte counts and amylase in urine and blood become normal quicker in the treatment group than in the control group. Moreover, patients intreatment group also had a higher cure rate, a lower complication rate and a shorter in-ward days compared with those in he control group. After treatment, the average value of P-VC was sign ificantly higher and the values ​​ofSIL-2R, TNF-α, IL-6 and IL-8 were significantly lower in the treatment group than in the control group (P <0.05 P-VC, P = 0.045; ; IL-6, P = 0.015; and IL-8, P = 0.043). Addition, the ratio of CD_4 / CD_8 and CD4 positive cells in the patients of treatment group weresignificantly higher than that of the control group aftertreatment (P <0.05.CD_4 / CD_8, P = 0.039; CD_4, P = 0.024) .CONCLUSION: High-dose vitamin C has therapeutic efficacy in acute pancreatitis. The potential mechanisms include stimulation of anti-oxidizing ability of AP patients, blockingof lipid peroxidation in the plasma and improvement of cellular immune function.