Background: The dysbiosis of the gut microbiota is a risk factor for breast cancer and could explain the difference in responses to therapy. Aim: To investigate the composition of different Lactobacillus species in patients with breast cancer compared to female control and in relation to different stages of breast cancer. Methodology: The study included 100 female patients with breast cancer and cross-matched 100 healthy controls. Stool samples were freshly collected for a multiplex polymerase chain reaction (PCR). identification of different Lactobacillus species