This study was designed and undertaken to test effects of dietary fiber supplement on constipation induced by antidepressants that leads to physical discomfort in depressed inpatients. The study was done with a non-equivalent pre-test/post-test experimental design using interviews, questionnaires, observational measurement. This study was conducted from December, 1994 to December 31st, 1995 using forty inpatients with major depressive disorders by the Diagnostic and statistical manual of mental disorders-Ⅳ(American Psychiatric Association, 1994) at three college hospitals. The forty inpatients(male ; 19, female 21) were conveniently divided into two groups : a control group of 22 and experimental group of 18 individuals. All of the subjects was revealed to have antidepressant-induced constipation during the first two weeks of control period. All of the patients had a control period of two weeks before and after an experimental period of three weeks. The experimental groups were given daily doses of 10g of alpha-cellulose and 5g of citrus pectin during the experimental period. The data gathered during the experiment was subsequently analyzed by means of statistical methods-multiple regression, t-test, ANOVA, and repeated measures ANOVA. Analysis of the difference in the stool frequency, amount of feces and severity of constipation according to time sequence was done using repeated measures ANOVA. Finally, multiple regression was used to analyze the major variables that influence the duration and degrees of constipation. 1. The results related to the stool frequency were as follows : a. The average frequency of defecation per week was significantly different between two groups, experimental group having significantly more than control group during experimental period and the first week after finishing treatment(p=0.0003, P=0.0001, p=0.0089, P=0.0018). b. For the change of the stool frequency between two groups over time, experimental subjects increased significantly more than control subjects(p=0.0001) c. The stool frequency was determined by the following variables : dietary fiber supplement, age, the number of admission and the amount of activity per week. 2. The results related to the amount of feces were as follows : a. For the amount of feces before and after treatment in two groups, experimental group had significantly larger amount than control group in the first, second, third, second, third weeks after beginning treatment and the first week after finishing treatment(p=0.0093, P=0.0007, p=0.0011, P=0.0025). b. For the change of the amount of feces between two groups over time, experimental subjects increased significantly higher than control subjects(p=0.0008) c. The amount of feces was determined by the following variables : dietary fiber supplement and the amount of activity per week. 3. The findings related to the severity of constipation were as follow : a. The severity of constipation was significantly different between two groups, experimental group having significantly lower scores than control group in the second, third weeks after treatment and the first week after finishing treatment(p=0.0220, P=0.0012, p=0.0045). b. The severity of constipation was determined determined by the following variables : dietary fiber supplement and the number of admission. In the light of these results, this study implies that dietary fiber supplement is effective in relieving antidepressant induced constipation in depressed patients.