Clinical bottom line Category of research Treatment. Number and type of study designs reviewed Three papers were critically reviewed. One was a prospective, randomised, blinded observational study, another was a randomised, placebo-controlled clinical trial, and the last was a non-randomised prospective, open-label clinical trial. Strength of evidence Weak. Outcomes reported The administration of trazodone to hospitalised dogs reduced several observed stress related behaviours compared to a control group that was environmentally matched to the treatment group (Gilbert-Gregory et al., 2016). In dogs subjected to postsurgical confinement at home, trazodone administration was not more effective at reducing stress related behaviours compared with a placebo in one study (Gruen et al., 2017); however, it was effective when observed in a non-placebo controlled clinical trial (Gruen et al., 2014). Further investigation with a larger sample size would assist in strengthening the evidence of an association between trazodone administration and a reduction in the behavioural signs of stress in dogs. Conclusion The available evidence weakly supports the hypothesis that administration of trazodone is an effective treatment in reducing stress related behaviours in hospitalised dogs and dogs confined post-surgery, and further studies are required to confirm its efficacy. The quality of the evidence when hospitalised dogs was studied was moderate (Gilbert-Gregory et al., 2016), however in dogs studied that were confined postsurgery, the evidence is weaker (Gruen et al., 2014; Gruen et al., 2017). Different trazodone doses were evaluated in the studies and so further studies focusing on dose effects are required to determine appropriate dose rates. Further studies also need to be conducted to evaluate the appropriate length of time that trazodone should be given prior to a stressful event, as well as whether trazodone needs to be used in conjunction with other anxiolytic drugs to optimise efficacy. How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.