Polymyxin B has become popular again in clinical practices due to dry antibiotic developments. Polymyxin B is produced by bacillus polymyxa, and the sulfate functions by binding to the cell membrane and interfering with its permeability. This type of chemical is used for the prevention of bacterial contamination of cell cultures. This antibiotic is highly active against gram-negative bacteria. Polymyxins are antibiotics that have recently regained public interest from the microbiology world due to the increasing number of infections related to drug-resistant, gram-negative bacteria. Polymyxin B is considered as a last-resort antibiotic in many scenarios where drug resistance is taking place. It is a selective supplement that is used for the isolation and enumeration of bacillus cereus from food samples, can also be used for the preparation of MYP agar for testing food samples.