Production is simple and relatively inexpensive Can be used without knowing exact characteristics of the disease-causing bacteria. Because of the high specificity of phages, the disease-causing bacterium has to be identified before the phage therapy can be started. Non-specific action that targets not only the pathogenic microorganisms but also a normal microflora. This can affect the microbial balance in the gut, which, in turn, often leads to serious secondary infections. Multiple side effects, including yeast infections, intestinal disorders, and allergies.
Production is expensive.
Phage therapy products were licensed for sale in the United States in 1930s. The Ministry of Health of the former Soviet Union routinely licensed active phage preparations for the use in humans. In the 1930s, a large US pharmaceutical company listed phages among its biological therapies and offered them for sale. Phages were used at the Institute Pasteur in Paris, France, and were sold in Eastern Europe, and all over the territory of the former Soviet Union. Bacteria can develop resistance against both antibiotics and phages.