Introduction: With the rise of the obesity epidemic in the United States over the last several decades and the medical complications seen with it, weight loss and dieting have become a national public health concern. Discussion: Because of their increased use and availability through internet sales, several different dieting agents were reviewed for potential toxicity. These included: syrup of ipecac, cathartics, human chorionic gonadotropin hormone, 2,4 Dinitrophenol, guar gum, phenylpropanolamine, ma huang/ ephedra, caffeine, clenbuterol, fenfluramine, sibutramine, thyroid hormone, orlistat and cannabinoid antagonists. Conclusions: With the internet making even banned products readily accessible, healthcare providers need to be aware of the potential toxicities of a wide range of weight loss agents. Our review covered topics we thought to be most historically significant as well as pertinent to the practice of medical toxicology today.