Antimicrobial chemotherapy is the clinical application of antimicrobial agents to treat infectious disease.There are five types of antimicrobial chemotherapy: antibacterial chemotherapy, antifungal chemotherapy, anthelminthic chemotherapy, antiprotozoal chemotherapy, and antiviral chemotherapy. Antimicrobial agents may be either bactericidal, killing the target bacterium or fungus, or bacteriostatic, inhibiting its growth. Bactericidal agents are more effective, but bacteriostatic agents can be extremely beneficial since they permit the normal defenses of the host to destroy the microorganisms.