Viral hepatitis can be divided into five types, designated A through E. Of these, types A and E enter the body orally and usually cause acute sickness, while B, C and D are transmitted through blood or other bodily fluids, and are more likely to result in chronic liver disease.
病毒性肝炎依病毒的種類，可分成 A 到 E5 種類型，其中 A、E 屬於「病從口入」型，是經口傳染（多為急性發作），B、C、D 則屬「你儂我儂」型，是經由血液、體液傳染，較容易變成慢性肝病。