Medical pharmaceutical and device manufacturers are essential in making products that benefit patients, and collaboration between health care clinicians and the industry is necessary for the design and manufacture of these medical products. However, health care clinicians must recognize that their duties and the interests of the industry may at times diverge. Relationships with the industry, even seemingly minor ones, have the potential to shape the decisions made on behalf of patients. The marketing divisions of pharmaceutical and medical device firms view health care clinicians as targets of their efforts, and some of the interactions that occur between the industry and health care clinicians have the potential to alter decision making in ways that may not necessarily benefit patients. Health care clinicians have an ethical duty to recognize situations and marketing strategies that are designed to influence their choice of diagnostic and therapeutic options for their patients. At a minimum, health care clinicians should be aware of the techniques used to attempt to alter their behavior and guard against them.