It has already been reported that baker′ s yeast-derived beta-glucan (BBG) prevented and reduced the incidence of allergic reactions. This study evaluated the effects of BBG on defecation frequency and fecal properties in female students. METHODS : Sixty healthy female students (age : 19.4+/-1.0) were divided into two groups for a single crossover study, and were given BBG (500m/day) or alpha cornstarch as a placebo. The study duration was 7 weeks with 5 periods consisting of 3 no-administration ones (Period 1, 3 and 5 : 1 week each one) and 2 administration ones (Period 2 and 4 : 2 weeks each one). The subjects answered the questionnaire about their defecation throughout the study. They were divided into 3 groups in accordance with the frequency of defecation in Period 1. Group 1 is one or more times a day, Group 2 is one time in two days, and Group 3 is one time in more than three days. RESULTS : 1 ) There was no effect of BBG on frequency or amount of stool in any group. 2) The form of stool significantly improved by BBG in group 3.3) BBG ingestion caused stool color to change from bright to dark in group 3 ( p <0.12). CONCLUSIONS : This study suggests that BBG improves the defecation of subjects who tend to be constipated.