Presentations and leaflets from pharmaceutical companies are still a major source of information for physicians in Japan. Most physicians trust them and base their clinical practice on them. Such products from pharmaceutical companies are just advertising, because they are profit-making enterprises. Gifts from pharmaceutical companies to health care providers introduce bias when prescribing medicine. Thus, it is important that health care providers who receive this information from pharmaceutical companies, interpret it correctly. There are several methods for information supplements used by pharmaceutical companies. The range of the vertical axis on a survival curve may not be the full range, and differences between treatment groups are expanded in graphs. Sometimes the shape of the survival curve is artificial. The treatment effects should be interpreted based on various indicators such as raw incidence, relative risk or the number needed to treat. A composite endpoint is often used in mega-studies because each individual outcome which comprises the composite endpoint has a small event rate that is not enough to reach statistical significance, whether outcomes are important for patients or not. Evidence-based medicine is a formulated method of clinical reasoning from evidence used to make decisions. We should consider not only the evidence, but also a patient's clinical state and circumstances, a patient's preferences and actions, and the clinical expertise of the health care providers. Although pharmaceutical companies seduce health care providers, they have to recognize the true magnitude of the effects of their products and recommend their use for patients carefully.
 <Author's abstract>