The onset of each type of viral hepatitis can be acute or slow, and the time between infection with each type of hepatitis virus and the appearance of clinical symptoms varies, from 4 (2-6) weeks for hepatitis A, 3 (1-6) months for hepatitis B, 40 (15-180) days for hepatitis C, 4-20 weeks for hepatitis D, and 6 (2-9) weeks for hepatitis E. The clinical course of viral hepatitis is divided into acute hepatitis, chronic hepatitis, heavy hepatitis (liver failure), biliary hepatitis, and hepatitis cirrhosis. Hepatitis patients may have the following clinical symptoms and signs according to the severity of the disease: 1, fever, more common in hepatitis A and E; 2, fatigue and weakness, especially when active; 3, gastrointestinal symptoms, including loss of appetite, anorexia, nausea, vomiting, belching, bloating, diarrhea and constipation; 4, pain in the liver; 5, respiratory symptoms, similar to the upper sensory symptoms, more common in children, mostly seen in hepatitis A; 6, jaundice performance Yellow urine and yellow eyes, usually yellow urine in the front; 7. dark skin is a sign of chronic hepatitis and cirrhosis; 8. itchy skin is mostly seen in biliary hepatitis; 9. spider nevus, liver palm, capillary dilatation is a sign of chronic hepatitis and cirrhosis; 10. edema is mostly seen in heavy hepatitis and cirrhosis decompensated stage; 11. bleeding phenomenon is mostly seen in heavy hepatitis (liver failure), severe chronic hepatitis and cirrhosis; 12. Liver odor is a kind of gas mixed with fecal odor and aromatic sweet smell exhaled by the patient when breathing, which often appears in hepatic coma; 13, hepatomegaly, tenderness and percussion pain in the liver area, splenomegaly, ascites and other signs.