Probiotics have gained widespread attention for their potential health benefits, particularly in promoting gut health and modulating the immune system. This article critically examines whether probiotics can be a universal remedy for all diseases, as often claimed in scientific literature and popular media. The objective is to evaluate the current scientific evidence regarding the efficacy of probiotics in preventing and treating various medical conditions, including gastrointestinal disorders, metabolic syndromes, allergies, and mental health issues. While some studies suggest promising outcomes in specific contexts, the evidence remains inconsistent and often limited to specific strains and conditions. Importantly, this review highlights that probiotics are not a one-size-fits-all solution and their effects can vary widely depending on individual physiology, dosage, and microbial composition. The article also addresses safety concerns, regulatory challenges, and the need for more rigorous, large-scale clinical trials. By analyzing existing data and expert opinions, this work aims to separate fact from hype and provide a balanced perspective on probiotics’ true potential and limitations in modern medicine.