Wilson's disease is a rare genetic disorder of copper metabolism with autosomal recessive inheritance. It occurs between the 6th and 45th year of life. An early and reliable diagnosis, if possible in the preclinical stage, is the prerequisite for starting therapy in time. By the treatment the quality of life and the expectation of life are raised considerably. If consistent treatment is given, there will be no objections to pregnancy in Wilson's disease. It should be interrupted only in case of marked portal hypertension and in the presence of oesophageal varices. The examination of the breast milk of a patient suffering from Wilson's disease showed a reduction in the trace elements copper and zinc. It may be necessary to think of copper and zinc substitution in children fed with breast milk only.