An ethnographic field study about the informed consent process in investigational drug trials for seriously ill persons with hepatitis C suggests that nurses and physicians referred to these trials as giving treatment, even though they involved placebos. Interview data and informed consent documents contained frequent references to the term `treatment trial' or `treatment'. Although these findings were unexpected and not the original focus of our study, we consider them in the light of an extensive literature on the `therapeutic misconception' that (...) has been described among physicians and patients with AIDS and other serious illnesses. We also suggest that certain organizational and professional characteristics of nursing and medicine reinforce this tendency to refer to the trials as treatment. Implications for further research are provided. (shrink)