同致癌物（英语：Co-carcinogen），亦称作助长物（英语：Promoter），为有助于癌细胞行成之作用者，有些致癌物不直接与DNA发生作用，而是透过不同的途径而引发恶性肿瘤，这些原发性的致癌含助长癌症形成作用。

zh-hans:黄曲毒素 zh-hans:双酚A

A Co-carcinogen is a chemical that promotes the effects of a carcinogen in the production of cancer. Usually, the term is used to refer to chemicals that are not carcinogenic on their own, such that an equivalent amount of the chemical is insufficient to initiate carcinogenesis. A chemical can be co-carcinogenic with other chemicals or with nonchemical carcinogens, such as UV radiation.