Probiotics, while widely recognized for their health benefits, have also been associated with several adverse effects, including opportunistic infections, immunological issues, allergic reactions, and the spread of antimicrobial resistance genes (ARGs). This review highlights recent studies on these risks, emphasizing the need for further research and caution in their use. Probiotics can cause systemic infections like sepsis and bacteremia, as well as localized infections such as endocarditis and abscesses. They may also lead to detrimental immunological effects, including autoimmune disorders, and allergic reactions. Additionally, probiotics may facilitate the transfer of ARGs, contributing to the spread of antibiotic resistance. Studies show that probiotic strains can transfer resistance genes to pathogens, increasing the risk of antibiotic resistance. The review also notes that probiotics may not effectively treat or prevent conditions like allergies, diabetes, or metabolic disorders. Despite their potential benefits, the risks associated with probiotics, particularly in vulnerable populations, necessitate careful consideration and further investigation. The review underscores the importance of understanding the adverse effects of probiotics to ensure their safe and effective use.Probiotics, while widely recognized for their health benefits, have also been associated with several adverse effects, including opportunistic infections, immunological issues, allergic reactions, and the spread of antimicrobial resistance genes (ARGs). This review highlights recent studies on these risks, emphasizing the need for further research and caution in their use. Probiotics can cause systemic infections like sepsis and bacteremia, as well as localized infections such as endocarditis and abscesses. They may also lead to detrimental immunological effects, including autoimmune disorders, and allergic reactions. Additionally, probiotics may facilitate the transfer of ARGs, contributing to the spread of antibiotic resistance. Studies show that probiotic strains can transfer resistance genes to pathogens, increasing the risk of antibiotic resistance. The review also notes that probiotics may not effectively treat or prevent conditions like allergies, diabetes, or metabolic disorders. Despite their potential benefits, the risks associated with probiotics, particularly in vulnerable populations, necessitate careful consideration and further investigation. The review underscores the importance of understanding the adverse effects of probiotics to ensure their safe and effective use.