The U.S. Food and Drug Administration (FDA) is advising consumers not to purchase “Japan Rapid Weight Loss Diet Pills Yellow,” which contains sibutramine and phenolphthalein. Sibutramine is a controlled substance that was removed from the market in October 2010 for safety reasons. Phenolphthalein is a solution used in chemical experiments and a suspected cancer-causing agent that is not approved for marketing in the United States. Read more.