Radioanalytical techniques have been applied in a study on (subclinical) hepatitis in Dobermann dogs. Cu levels in transcutaneous obtained full liver biopsies were quantified using INAA and 66Cu. A copper excretion study was performed in a group of completely normal Dobermann dogs and in six Dobermanns with elevated copper levels and suffering from subclinical hepatitis. 64Cu2+ was used to assess whether a normal bile flow and thus excretion was possible. All subjects underwent separately from this 64Cu2+ excretion study a 99mTc-Bis-IDA scintigraphy. The Cu levels in liver of these hepatitis patients vary from 600 to 1600 mg . kg-1 whereas 100-300 mg . kg-1 is probably normal for healthy Dobermann dogs. These Cu levels match fully with histopathology results and clinical observations. Measurements during a 2 years' evaluation period showed a clear relation between the existence of subclinical hepatitis and increased Cu levels without a sign for cholestasis or an abnormal bile flow.