Four different dosage regimens of interferon (IFN) alfa-2b (3 million units (MU) three times weekly for three months, 3 MU three times weekly for six months, 6 MU two times weekly for six months, and 6 MU three times weekly for six months) were compared in patients with chronic hepatitis C. There was no significant difference measured by percentage of responders to treatment between the four groups, but the degree of response was inversely correlated with the severity of liver damage. Viraemia was undetectable in most (75%) of responders treated with interferon and also in 20% of those who did not respond to treatment.