Discussions having lately raised the importance of rest in the treatment of viral hepatitis the authors report some studies made on the subject. They take into account 3 personal unpublished statistics analyzing the role of effort at 3 different stages -- in the acute phase, during convalescence and as an eventual factor producing aggravation. Although their results appear to be in contradiction with those found in American studies the authors show that the importance of rest in the initial phase is unanimously recognized and that there is no statistical evidence that such a prescription should be given up before the normalization of the main biological parameters. Furthermore though it is statistically proved that a certain activity between the 30th and 60th day does not affect the later course of the disease yet there is no element which allows to authorize the patient to resume his normal professionnal activity before the 60th day. Finally the lack of controlled studies does not allow any precise determination of the impact of effort in the determinism of an eventual aggravation. However according to the authors' experience physical tiredness can legitimately be suspected to have produced this aggravation in 47.06 % of cases of a secondarily aggravated hepatitis.