This randomized phase I trial is studying the side effects and best dose of diindolylmethane
in healthy volunteers. Chemoprevention is the use of certain drugs or substances to keep
cancer from forming, growing, or coming back. The use of diindolylmethane may keep cancer
from forming. Collecting and storing samples of blood and urine from healthy volunteers to
study in the laboratory may help doctors learn more about the way a person's body handles the
drug.