The carcinogenicity of caffeine and coffee: a review.

This article reviews 18 years of research on the carcinogenic effects of both caffeine and coffee. Caffeine, the most widely consumed drug in the United States, has been the subject of numerous studies. It has been found to both increase and decrease malignant cell development, on the cellular and subcellular level, depending on the carcinogen it is used with, the type of host cell, and the stage of cell cycle in which it is introduced. No causal relationship has been established between coffee intake and lower urinary tract cancer, pancreatic cancer, breast cancer or fibrocystic breast disease, ovarian cancer, or large bowel cancer.