Drugs are generally used in the treatment of infectious disease caused by microbes. This era of antimicrobial chemotherapy was discovered in the early 1099’s where the growth of this increased in an efficient way by the past years. The drugs used are generally acts in such a way by the selective toxicity, by the inhibition of the cell membrane and by the syntheses and function of the proteins. This clinical application where the resistance involves the reduced entry of drug and changes in the target of the drug. This metabolic inactivity of the drug is antimicrobial chemotherapy.