Aims: Analysis of inflammatory immune response upon bacteriophage intake in mice. Methods and Results: Bacteriophage therapy is emerging as an effective alternative to conventional antibiotics. However, its safety when applied to humans and animals remains a prime concern. This study investigated the inflammatory responses in mice fed orally with bacteriophages. The mice were fed with either murine norovirus (MNV) or bacteriophage T7 for 10 days and then sacrificed. No behavioural changes related to diet, movement or defecation were observed in either group. The inflammatory cytokine profiling showed an increased level of interleukins 1 alpha (IL-1 alpha), 1 beta (IL-1 beta), 2 (IL-2), 10 (IL-10), 12 (IL-12), 17A (IL-17A), interferon-gamma (IFN-alpha), tumour necrosis factor-alpha (TNF-alpha), granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) in the serum from the mice fed with MNV, whereas only a slight increase in IL-17A was observed in the serum from the mice fed with bacteriophage T7. A histopathological analysis of tissue samples from the stomach, small intestine and colon revealed no significant pathological change. Conclusions: The bacteriophage diet only caused a minimal inflammatory response in the mice. Significance and Impact of the Study: This study provides insights into safety concerns of orally fed bacteriophage therapy.