The targets of antimicrobial drugs are: inhibition of RNA synthesis, inhibition of DNA replication, inhibition of cell wall synthesis, inhibition of protein synthesis, inhibition of enzyme activity, and disruption of plasma membrane. Each of the drugs affects a different part of the cell, and only affects that one part. The drug will inhibit the bacterial cell, but not the host cells because they will perform the same cell functions using a different method or getting energy/food using a different source. This is done in order to stop a microbe from growing and replicating. The drug must be chosen based on the microorganism that needs to be fought. If the wrong one is chosen, it will most likely not affect the bacteria as intended. Also the wrong drug could kill/harm our cells or our normal flora.