To study the influence of interferon therapy on soluble intercellular adhesion molecule-1 we measured sICAM-1 levels in 22 patients with type C chronic hepatitis treated with interferon. We also studied 9 healthy subjects as control group. The results showed statistically significant higher levels of sICAM-1 in patients with liver disease than in the controls. The sICAM-1 baseline levels were similar in patients with chronic active hepatitis or cirrhosis but, during therapy, these levels decreased only in patients with chronic hepatitis. After IFN withdrawal sICAM-1 levels rebounded to initial values.