Phage therapy is a treatment method that uses bacteriophages, which are viruses that infect bacteria, to treat bacterial infections. Phages are natural adversaries, helping to restrict their proliferation in the natural environment. Phages are made up of DNA or RNA in a protein capsid and cannot multiply independently, relying on bacterial hosts to live. The use of antibiotics in people and animals is a key contributor to antimicrobial resistance (AMR), a serious public health concern in the twenty-first century. Compared to traditional antibiotic treatments, phage therapy has several advantages, including automatic dosing, low inherent toxicity, and the ability to use low doses. Phages infect bacteria, reprogramming the cell to become a phage factory, and producing new phage particles that lyse the cell and release more phages. Some phages have a temperate life cycle in which infected cells carry the phage genome indefinitely in a dormant state. Since 1919, phage treatment has been used to treat diseases such as Shigella dysenteries and has the potential to be utilized to treat antibiotic-resistant bacteria.