Background　According to a survey by the Ministry of Health, Labour and Welfare, the number of people with a tendency to constipation is continually increasing with a decrease in the consumption of dietary fiber.
Purpose　We evaluated the improvement of bowel movement and fecal odor after consumption of dietary fiber-rich cocoa.
Methods　The test food, containing 10 g cocoa（1.5 g lignin）, and cocoa-flavored control food that did not contain any cocoa were prepared. A crossover study was then conducted with 22 healthy male and female subjects aged between 20 and 60 years with a tendency to constipation, who were randomly allocated to the two groups. Participants in each group consumed either the test or control food and alternated this every 2 weeks. Defecation frequency, volume, characteristics, and odor were evaluated using a questionnaire, and fecal ammonia, indole, and skatole concentrations were determined quantitatively.
Results　Consumption of the test food significantly increased defecation frequency and the defecation volume also tended to increase, and significantly reduced fecal ammonia concentration.
Conclusion　Consumption of 10 g cocoa once a day for 2 weeks improved defecation frequency and fecal odor in the test subjects. The principal ingredient contributing to both improvements is thought to be lignin, an insoluble dietary fiber contained in cocoa.