BackgroundPets offer significant health benefits, from decreased cardiovascular risks to anxiety and post-traumatic stress improvements. Animal-assisted interventions (AAI) are not frequently practiced in the intensive care unit (ICU) for fear of health risk for critical patients because there is a hypothetical risk of zoonoses.ObjectivesThis systematic review aimed to collect and summarize available evidence about AAI in the ICU. The Review questions were “Do AAI improve the clinical outcome of Critically Ill Patients admitted to ICUs?” and “Are the zoonotic infections the cause of negative prognosis?”.MethodsThe following databases were searched on 5 January 2023: Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, and PubMed. All controlled studies (randomized controlled, quasi-experimental, and observational studies) were included. The systematic review protocol has been registered on the International Prospective Register of Systematic Review (CRD42022344539).ResultsA total of 1302 papers were retrieved, 1262 after the duplicate remotion. Of these, only 34 were assessed for eligibility and only 6 were included in the qualitative synthesis. In all the studies included the dog was the animal used for the AAI with a total of 118 cases and 128 controls. Studies have high variability, and no one has used increased survival or zoonotic risk as outcomes.ConclusionsThe evidence on the effectiveness of AAIs in ICU settings is scarce and no data are available on their safety. AAIs use in the ICU must be considered experimental and follow the related regulation until further data will be available. Given the potential positive impact on patient-centered outcomes, a research effort for high-quality studies seems to be justified.Supplementary InformationThe online version contains supplementary material available at 10.1186/s44158-023-00100-y.