Introduction: The therapeutic use of animals has been debated for decades, and its use explored in a variety of settings and populations. However, there is no uniformity on naming these interventions. Evidence based knowledge is essential to implement effective strategies in hospital. This review focused on the use of animal programs for hospitalized patients, and considered the potential risks. Methods: The following databases were searched: PubMed, Scopus, PsychInfo, Ebsco Animals, PROQUEST, Web of Science, CINAHL, and MEDLINE, and PRISMA guidelines were adhered to. Results: Out of 432 articles were identified 36 articles suitable for inclusion into the review. Data was heterogeneous in terms of age of patient, health issue, animals used and the length of interactions, which made comparison problematic. Studies on children, psychiatric and elderly patients were the most common. The animal-intervention programs suggested various benefits such as reducing stress, pain and anxiety. Other outcomes considered were changes in vital signs, and nutritional intake. Most studies used dogs, but other animals were effectively employed. The major risks outlined were allergies, infections and animal-related accidents. Zoonosis was a possible risk, as well as common infections as Methicillinresistant Staphylococcus Aureus. The implementation of simple hygiene protocols was effective at minimizing risk. The literature suggested that the benefits outweighed by far the risks. Conclusion: The human relationship with animals can be useful and relatively safe for inpatients with various problems. Moreover, the implementation of security precautions and the careful selection of patients should minimize the risks, particularly those infection-related. Many aspects remain unclear, further studies are required. (C) 2016 Elsevier GmbH. All rights reserved.