Methylene Blue Solution is widely used in medical and biological fields. In medicine, it serves as a treatment for methemoglobinemia, a condition where blood cannot carry oxygen effectively. It acts by converting methemoglobin back to hemoglobin. Additionally, it is utilized as a dye in surgical procedures to mark tissues or identify anatomical structures. In microbiology, it is employed as a staining agent to visualize bacteria and other microorganisms under a microscope. It also plays a role in diagnostic tests, such as the methylene blue reduction test, to assess milk quality or microbial activity. In aquaculture, it is used to treat fungal and parasitic infections in fish. Furthermore, it has applications in research, particularly in studying mitochondrial function and oxidative stress.