Persons taking part in a clinical study are patients in the need of treatment. Although the values of the study and the treatment are largely consistent with each other, their goals, methods and ethics differ. Randomized studies in particular involve features that are strange to conventional treatments, such as blinding and placebo medication. Anyone participating in a study should understand that instead of obtaining a health benefit for an individual participant, its primary goal is generalizable knowledge. Any misunderstanding of the therapeutic meaning of the study may lead to disappointment of the participant.