Faecal microbiota transplantation (FMT) is effective for patients with recurrent Clostridium difficile infection (CDI). However, the mechanisms of FMT remain poorly understood and, despite data suggesting that bacteriophages influence the success of FMT, data on viral alterations in CDI and their effects on clinical outcome are scarce. In a preliminary study, Zuo et al. used ultra-deep metagenomic sequencing to compare enteric virome changes in patients with CDI (n = 24) with healthy controls (n = 20), longitudinally assessing alterations in nine patients after FMT. Patients with CDI were found to have a higher abundance but lower diversity of the bacteriophage Caudovirales compared with controls, suggesting enteric virome dysbiosis in CDI. Furthermore, cure after FMT was more likely when an increased fraction of the recipient enteric virome was occupied by donor-derived Caudovirales taxa, suggesting that bacteriophages might play a role in FMT efficacy.