Since the 1950s, researchers have gradually realized that the body's bacteria help fight infection by crowding out potential pathogens. In the past decades, scientists have even begun to see our microbiota as thick‑and‑thin allies. However, the influence of gut bacteria on HIV is largely unknown. Our review likely sheds light on the previously indistinct role of commensal microbiota in retroviral pathogenesis. The delicate yet critical balance between this enormous bacterial population and the gastrointestinal tract is gradually destroyed along with HIV incursion. The leakage into the systemic circulation of bacterial and byproducts such as lipopolysaccharide directly stimulates the innate immune system through toll‑like receptors. As a result, toll‑like receptor‑4 activation provokes production of interleukin‑10, which mediates immunological tolerance. Therefore, a solid deduction is that intestinal microbes may be involved in triggering of replication and transmission of HIV, just like other retroviruses.