This invention relates to methods of aiding smoking cessation and/or treating and/or preventing smoking addition or methods of treating and/or preventing nicotine or nicotine-derived compounds or estrogen induced breast cancer, which comprises administering to a subject an effective amount of a tea polyphenol. The invention uses catechins (such as epigallocatechin gallate (“EGCG”), epigallocatechin (“EGC”), epicatechin gallate (“ECG”), epicatechin (“EC”), gallocatechin gallate (“GCG”), gallocatechin (“GC”), catechin gallate (“CG”) and catechin (“C”)) in aiding smoking cessation and/or treating and/or preventing smoking addition or treating and/or preventing nicotine or nicotine-derived compounds or estrogen induced breast cancer.
