The treatment of chronic hepatitis C, now well codified with the association of a pegylated interferon alpha and ribavirine, allows to obtain a prolonged virological response in more than half of the cases. The results are even better and reach about 70% of success when the treatment is optimized. In spite of these therapeutic advances, a substantial percentage are non responders or relapsers, mainly because of adverse effects of the treatment which lead to dose reductions or premature discontinuation. The main side effects involved in treatment modification are fatigue, muscular and articular pains, disturbance the humor, insomnia, depression, anaemia and leucopenia. These adverse effects can modify the quality of life of the patients considerably. Thus it is important to take care of them quickly after their appearance or even to try to anticipate them. It is also essential to provide a well adapted therapeutic education to get an optimal compliance to the treatment and thereby a better chance of success.