The long term efficacy of low residue diet (LRD) for the maintenance of remission in patients with Crohn's disease was studied. The patients consisted of 60 with quiescent Crohn's disease who were given LRD (Clinimeal or Ensure Liquid) for maintenance therapy for more than one year (average 2.4 years) after discharge from our institute. On the basis of the quantity of LRD given per day, the patients were classified into three groups: A; O to 799 kcal a day, B; 800 to 1599 kcal a day and C; more than 1600 kcal a day. The remission rate and the avoidance rate of admission were calculated and compared among three groups. The remission rate in group C was significantly higher than those in groups A and B. The avoidance rates of admission in groups B and C were significantly higher than that in group A. These results suggest that drinking of LRD at home is useful for the maintenance of remission in patients with Crohn's disease and that the effect of LRD depends on the quantity of LRD given per day.