In 1983, the regulation on reporting transmissible diseases was extended. At that time, the doctors were obliged to report all cases of acute viral hepatitis to the Cantonal physician. The Federal Office of Health commissioned a statistical evaluation of the reports from the years 1984 to 1987. Of the 4543 reports analysed, 40% relate to hepatitis A, 47% to hepatitis B and 7% to non-A non-B hepatitis. Men suffered hepatitis more frequently than women, with the exception of the non-A non-B hepatitis, where the sexes are roughly equally represented. Adolescents and young adults are the most frequently affected age group for all types of hepatitis. Those dependent on drugs have a particularly high risk of infection for all types of hepatitis. The cases of hepatitis occurring after journeys abroad are even more significant in terms of numbers. The medical personnel can no longer be regarded as a high-risk group. An age-standardized comparison shows that, with regard to hepatitis B, the risk for men in medical professions is the same as the average risk for all men, while the risk for women is still slightly higher than that for the female population as a whole.