The intake of dietary fiber necessary for amelioration of hypercholesterolemia and prevention of ischemic heart disease and diabetes mellitus was tentatively assessed by searching articles from databases on the Internet such as Medline, Chemical Abstracts, etc. The values obtained were much higher than those in the Recommended Dietary Allowances for the Japanese, Sixth Revision, in which 20-25g/day (10g/1, 000kcal) is set as the adequate dietary intake level for adults. In view of the average intake of dietary fiber among Japanese people, which is assumed to be about 16g/day, efforts should be made to attain at least the recommended level. In addition, as the amelioration and prevention of the above disorders are accomplished by water-soluble dietary fiber, the intake of this type of fiber, as well as total dietary fiber, should be increased.