Fibrocystic breast disease (FBD) is common in women. Caffeine-containing foods and beverages have been implicated as a cause of FBD or as an important factor in its progression. Relationships of causation are difficult to demonstrate. Only rigorous investigational methods can show true association between cause and effect. Our critical review of the medical literature indicated that there is weak evidence for an association between caffeine and FBD. We conclude that physicians need not recommend the avoidance of caffeine in otherwise healthy women who have FBD.