Research on why patients sometimes choose non-proven therapies (NPT) instead of conventional treatments is limited. We investigated how physician likeability influences the choice of NPT instead of conventional treatment. In an experiment with three medical scenarios, participants (N = 384) consulted two physicians who gave conflicting recommendations: The first physician recommended a conventional treatment and the second one recommended a NPT. We manipulated the likeability of the first physician, who was either likeable or unlikeable. Using mediation analyses, we explored how the effect of likeability was channelled and whether time pressure influenced treatment choice. Participants chose the NPT more often (OR = 1.43, 95% CI [1.03–2.00]), had more positive affective responses, and perceived more benefit from NPT when the conventional treatment was recommended by an unlikeable (vs. likeable) physician. Time pressure had no effect on treatment choice. Physicians’ likeability might play an important role in treatment choice in the presence of conflicting information. Providers should be cognizant that poor communication might push patients to prefer the advice of more likeable physicians, even when they prescribe NPT instead of conventional treatment.