Only patients with hepatitis C diagnosed as serum HCV RNA positive require antiviral therapy. (1) Acute hepatitis C. IFNα treatment significantly reduces the chronicity rate of acute hepatitis C. Therefore, antiviral treatment should be started if HCV RNA positivity is detected. There is no uniform protocol for the treatment of acute hepatitis C. It is recommended to give ordinary IFNα 3MU, intramuscular or subcutaneous injection once every other day for 24 weeks, and ribavirin 800~1000mg/d should be taken at the same time. (2)Chronic hepatitis C. ①People with persistent or repeated elevation of ALT or AST, or liver histology with obvious inflammatory necrosis (G≥2) or moderate or more fibrosis (S≥2) are prone to progress to cirrhosis and should be given active treatment. (ii) Most of those with persistently normal ALT have mild liver lesions, and the decision to treat should be based on the pathologic results of liver biopsy. For those with obvious fibrosis (S2, S3), antiviral treatment should be given regardless of the degree of inflammatory necrosis; for those with mild inflammatory necrosis and no obvious fibrosis (S0, S1), no treatment can be given for the time being, but the liver function should be tested every 3 to 6 months. (iii) ALT level is not an important predictor of patient response to IFNα. It has been previously reported that the treatment of hepatitis C patients with normal ALT with ordinary IFNα has no significant effect, and thus the application of IFNα treatment is not advocated. However, a recent study found that the virologic response rate of hepatitis C patients with normal ALT treated with PEG-IFNα-2a in combination with ribavirin was similar to that of hepatitis C patients with elevated ALT. Therefore, patients with hepatitis C with normal or mildly elevated ALT can also be treated as long as they are HCV RNA positive, but more cases need to be accumulated for further study. (3) Hepatitis C cirrhosis: ① patients with compensated cirrhosis (Child-Pugh class A), although the tolerance and effect of the treatment is reduced, in order to stabilize the condition, delay or prevent the occurrence of liver failure and HCC and other complications, it is recommended to give antiviral treatment under close observation. (2) Patients with decompensated cirrhosis, who are mostly difficult to tolerate the adverse effects of IFNα treatment, should undergo liver transplantation if available. (4) Hepatitis C recurrence after liver transplantation: patients with HCV-related cirrhosis or HCC have a high rate of recurrence of HCV infection after liver transplantation.IFNα treatment is effective for such patients, but there is a possibility of promoting the rejection reaction to the transplanted liver, and antiviral treatment can be given under the guidance of experienced specialists and close observation.