An antibiotic is a chemical substance produced by a microorganism (bacterium, yeast, or

mold) that inhibits (bacteriostatic) or kills (bactericidal) bacteria, fungi, or parasites. The

use of antibiotics (penicillin was first in general use in the 1940s) has made it possible to

cure many conditions such as pneumonia, urinary tract infection, and streptococcal

pharyngitis (“strep throat”). Caution about the use of antibiotics is warranted because they

are powerful agents. Like all drugs, they have side effects. Also, with indiscriminate use of

antibiotics, bacteria and fungi can develop resistance to a particular agent. Infections

caused by these resistant bacteria can spread and may be difficult or impossible to cure.

Antifungal drugs treat fungal infections. These infections commonly occur in the skin

(ringworm), vagina (moniliasis or candidiasis), mouth, bloodstream, or lungs. Antitubercular

drugs treat tuberculosis, a chronic and often drug-resistant infection.

Antiviral drugs are used against infections due to viruses, such as herpesviruses,

Epstein-Barr virus, cytomegalovirus (CMV), human immunodeficiency virus (HIV), and

hepatitis C virus.

Types of antibioticsand antiviral drugs are listed such as amphotericin B (Fungilin) and acyclovir (Zovirax), etc..