The pattern of metabolites of ciclosporin in blood and 24 h-urine of 58 liver graft recipients was routinely monitored by HPLC from transplantation until discharge from hospital. Liver function and ciclosporin metabolite pattern in patients with an uncomplicated clinical course and in those with cholestasis or acute rejection were compared. During cholestasis M19 and M1A, and during acute rejection M19, in blood were significantly elevated compared to the control group. Blood M19 was significantly correlated with bilirubin concentration and gamma-glutamyl transferase activity in serum, and M1A with the serum bilirubin concentration. Analysis of the metabolite pattern over the observation period showed higher concentrations of M19 and M1A in blood from patients with cholestasis and acute rejection than in the control group; concentrations were lower in the rejection group than in the cholestasis group. The metabolite pattern in 24 h-urine showed similar alterations in ciclosporin metabolite pattern to those in blood. Cholestasis and rejection shift the ciclosporin metabolite pattern in blood and urine to higher concentrations of M19 and M1A, whereas the concentrations of other metabolites and ciclosporin were not significantly affected.