Scientists and experts using social media platforms to engage with the public risk negative public feedback, potentially harming their efforts. This paper addresses how negative user comments affect experts’ trustworthiness and the messages’ credibility depending on whether they frame their message as scientific versus anecdotal using an online study with a 2 (evidence type: scientific vs. anecdotal) x 3 (comments: neutral, negative-factual, negative-emotional) between-subjects design. The results suggest that relying on scientific evidence when engaging in emotionally charged discourses is beneficial. Negative-emotional comments have a significant negative impact on trustworthiness, which is especially pronounced when using anecdotal evidence.