“…On the other hand, oral mucositis and oral health stand as one of the most treated side effects as they significantly reduce the patients’ quality of life [ 60 ]. In that matter, probiotics such as B. longum (BCMC02120, BB-536), L. lactis BCMC12451, E. faecium , and L. brevis CD2 have shown to reduce the incidence of severe oral mucositis by promoting the growth and protection of the bacterial flora and, as a result, decreasing the number of adverse effects, severity, and incidence of mucositis [ 20 , 40 , 41 , 42 ]. These findings are in agreement with those of Vesty and collaborators (2020) [ 41 ], who identified that using S. salivarius M18 improved patients’ quality of life by reducing the number of oral infections (candidiasis) and adverse effects (mucositis, diarrhea) that these patients experienced after their treatments.…”