The pharmaceutical industry spends more time and resources on generation, collation, and dissemination of medical information than it does on production of medicines. This information is essential as a resource for development of medicines, but is also needed to satisfy licensing requirements, protect patents, promote sales, and advise patients, prescribers, and dispensers. Such information is of great commercial value, and most of it is confidential, protected by regulations about intellectual property rights. Through their generation and dissemination of information, transnational companies can greatly influence clinical practice. Sometimes, their commercially determined goals represent genuine advances in health-care provision, but most often they are implicated in excessive and costly production of information that is largely kept secret, often duplicated, and can risk undermining the best interests of patients and society.