Anonymous student evaluation of teaching (SET) is a universal practice in higher education. We conducted a mixed-methods approach to investigate the nature and impact of anonymous SET commentary in the Australian higher education sector. Respondents shared a range of detailed SET exemplars, which revealed the extent of hurtful, defamatory and abusive commentary made by students. This paper reports the self-perceived impact of these on the health and wellbeing of academics. The majority of respondents reported that anonymous narrative comments contributed to workplace stress. There were no significant differences for gender. Younger academics were more likely to report the process of SET as stressful. Four themes were identified from the narrative responses: stress, distress, disorder and coping. These themes highlight the mental distress and impacts on well-being from repeated exposure to uncivil commentary made in SET by students. This distress was exacerbated by the failure of many employing universities to take substantial action to remedy or limit exposure to uncivil behaviour. The current system of anonymous SET has little validity and instead may operate as a vehicle for unfettered incivility directed towards teaching staff. The mental health impacts are significant for some and may impact the recruitment, retention and renewal of academic teaching staff into the future.