Small intestinal bacterial overgrowth (SIBO) has recently garnered significant attention from both medical professionals and the general public, likely due to its increasing prevalence and advancements in testing technology. However, the accuracy of breath tests in clinical practice for diagnosing SIBO still requires thorough validation. This review compiles the definition, etiology, influencing factors, novel testing methods, and the determination and interpretation of SIBO results. We particularly discuss the various controversies and limitations associated with these tests. By comparing and evaluating the advantages and disadvantages of different diagnostic methods fo rSIBO, we aim to enhance the understanding of its clinical diagnosis and promote future research focused on accurate detection methods.