Recently, false rumor about leukemia went around Japan. The rumor was that the number of patients of leukemia becomes 7 times after the N-plant crisis which was not true. Most of us know that leukemia can be caused by radiation and one TV announcer got leukemia. Therefore, we believed the false rumor and it was difficult to tell us that “this is not true” by doctor association. The doctor should not hide anything and show the trend clearly then we can believe. A lot of peoples are worry about leukemia so the trend should be informed then it can release the stress of people if the trend does not change before / after the incident.