Mr. Zhang was found to be positive for hepatitis B surface antigen (HBsAg), e antibody and core antibody (“small triplet”) in his medical checkup 5 years ago, but his liver function tests were normal, and the doctor at the time told him to take rest, avoid overexertion and drink less alcohol, so he rarely drank alcohol, paid attention to maintenance and enhanced nutrition. In the past two years, his body shape has gradually become more and more healthy. The doctor recommended the injection of long-acting interferon against chronic hepatitis B treatment. After half a year of treatment, the blood level of hepatitis B virus (HBV-DNA) decreased significantly, but the transaminases increased instead of decreased. Later, the patient came to the famous hepatologist Prof. Fan Jiangao for medical treatment, and Prof. Fan, considering his fat body type, gave him blood lipid, blood sugar, liver ultrasound and liver biopsy histology, and diagnosed him with “non-alcoholic steatohepatitis, chronic hepatitis B virus infection status”. After a combination of diet control, moderate increase in exercise and liver-protective drugs, the patient lost weight within 3 months, and his lipids and transaminases returned to normal on rechecking, and ultrasound showed that the liver fat had subsided. Patients with chronic hepatitis B should not simply assume that the increase in transaminases is due to hepatitis activity and antiviral treatment. In fact, it is more likely that the liver function is abnormal due to obesity, dyslipidemia, fatty liver, as well as alcohol and drugs, etc. At this time, antiviral treatment alone will certainly not have the effect of protecting the liver and lowering enzymes. This patient is a chronic hepatitis B virus infection combined with fatty liver, due to lipid droplet compression of hepatocyte membrane, membrane permeability increased resulting in intracellular transaminase infiltration into the serum, serum transaminase is elevated, at this time, liver preservation and lipid removal is the most urgent. So how should we determine whether elevated transaminases are caused by fatty liver or the presence of hepatitis activity? Generally speaking, if there is clinical suspicion of fatty liver, serum triglyceride and cholesterol levels and ultrasound should be routinely checked, although some patients with fatty liver may be missed by these means alone. Therefore, a comprehensive examination, including a CT scan, is still needed to make a comprehensive judgment and, if necessary, a liver biopsy. The most reliable way to determine the presence of hepatitis activity is to perform a liver biopsy, or of course, to try to increase activity to detect changes in transaminases. Treatment of chronic hepatitis B combined with fatty liver should be differentiated according to the different clinical types. For fatty liver combined with chronic hepatitis B viral infection, treatment focuses on fatty liver and its underlying disease, and most do not require antiviral therapy; for hepatitis B combined with fatty liver, both antiviral therapy and fatty liver treatment should be combined. If the patient is in the active phase of hepatitis, rest should be emphasized and the treatment of hepatitis should be the focus, and the fatty degeneration in the liver can be significantly reduced after effective antiviral therapy; if the hepatitis is in the stable or recovery phase, the patient should be allowed to gradually increase the activity to control the weight and then consider the regular antiviral therapy. We know that if the cause of simple fatty liver is removed and the primary underlying disease is controlled in time, the fatty deposits in the liver will completely subside within a few months. So for patients with chronic hepatitis B combined with fatty liver, can fatty liver be reversed? The answer is yes, as long as it is treated early, fatty liver can be cured, but of course, if the disease has progressed to the stage of steatohepatitis, it will take half a year or even several years to fully recover. In short, the treatment of patients with hepatitis B combined with fatty liver is not limited to drugs. For obese fatty liver patients, non-pharmaceutical measures such as diet therapy, exercise therapy, and lifestyle changes are far more effective than drugs alone. For alcoholic fatty liver abstain from alcohol. In recent years, the incidence of fatty liver is on the rise year by year. According to the medical examination center medical examination information: Beijing adult fatty liver prevalence is 17.29%, Shanghai is 17.80%, Guangdong is 15.21%. The prevalence rate in Shanghai has doubled in the past ten years. Due to the increasing incidence of childhood obesity, the prevalence of obese children is even higher, with 22.5% to 52.8% in Europe and the United States. The proportion of hepatitis B combined with fatty liver is also increasing, is there a causal relationship between the two? The first is the combination of fatty liver in patients with hepatitis B. Most of them are recovering from hepatitis and overemphasize rest and nutrition, which leads to fatty liver suddenly; the second is fatty liver first and then infected with hepatitis B virus. The third is the presence of chronic hepatitis B virus infection first, followed by the development of fatty liver. Chronic hepatitis B in combination with fatty liver can greatly reduce the efficacy of antiviral treatment, resulting in slow onset and lower efficiency of antiviral treatment. Therefore, fatty liver should be actively treated as early as possible so that fatty liver, which is relatively easy to treat and control, can be cured early and roadblocks to antiviral treatment can be removed. There are three core issues in the treatment of hepatitis B combined with fatty liver: antiviral therapy for hepatitis B, removal of fatty liver and prevention of cirrhosis. Therefore preventing hepatitis B and fatty liver from progressing to cirrhosis and liver cancer is the main treatment objective.