BACKGROUND: Recent studies suggest that displays of unacceptable behaviour, including bullying, discrimination and harassment, between healthcare workers (HCWs) may impair job performance, and in turn, increase the frequency of medical errors, adverse events and healthcare-related complications. The objective of this systematic review was to summarise the current evidence of the impact of unacceptable behaviour occurring between HCWs on clinical performance and patient outcomes. METHODS: We searched MEDLINE, Embase, PsycINFO and CINAHL from 1 January 1990 to 31 March 2021. The search results w...