The purpose of this study was to find out the prevalence of constipation nutrition knowledge on dietary fiber and frequency of dietary fiber foods intake of 3rd grade high school girls in Kangnung and Seoul. The total 412 questionnaires were analyzed. Defecation frequency was irregular in 47.6% of the students 21.6% had less than twice a week. Those who were in a hurry during defecation frequency was irregular in 47.6% of the students 21.6% had less than twice a week. Those who were in a hurry during defecation were 57.9% and those spent more than 10 min. for defecation were 21.8% More than half of the students(56.6%) answered to have constipation and 13.8% had taken laxative pills more than once during the last one month period. The nutrition knowledge score was relatively high 7.63 points out of possible 10. Dietary fiber intake scores measured by food frequency questionnaire were 3.78 for fruits 3.71 points out of possible 10. Dietary fiber food intake scores measured by food frequency questionnaire were 3.78 for fruits 3.71 for vegetables and 3.37 for seaweeds meaning taken once a week to 2-3 times per month. For the diagnosis of defecation difficulty a factor called "constipation index" was introduced which was composed of defecation frequency time spending for defecation easiness in defecation and feeling of residue in the intestine after defecation. The Cronbach a coefficient of constipation index was 71. Constipation index was significantly correlated with stress level(p<0.05) haste during defecation(p<.01) and defecation time(p<.01) The higher the stress level the more hurry during defecation and the later the defecation the higher the constipation index. The students who ate more often vegetables and seaweeds had lower constipation index(p<.05, p<.01)05, p<.01)