Purpose - This study aims to investigate how unethical corporate behavior of pharmaceutical companies affects consumer behavior of German consumers, especially boycotts of over-the-counter drugs.Design methodology approach - Borrowing from psychological theory as well as consumer behavior theory, the study develops a conceptual model that considers affective and cognitive determinants of boycotting behavior. Within the scope of the German pharmaceutical sector, the researchers conducted a survey to validate the research hypotheses using moderated regression analysis.Findings - Individuals' inclination to join boycotts and engage in boycott communication results from anger about animal testing, perceived immorality of pharmaceutical companies' corporate behavior and negative corporate image of pharmaceutical companies. An empirical analysis reveals significant moderation effects.Research limitations implications - This research focuses on the pharmaceutical sector and the boycott of over-the-counter drugs.Practical implications - The study results may help pharmaceutical companies develop communication responses to accusations of unethical corporate behavior.Originality value - The paper offers new insights on the effects of unethical corporate behavior on consumers, which may be useful to the crisis-prone pharmaceutical sector.