Antibiotics (antibacterials) were one of the discoveries that has revolutionized today’s medicines and has saved many lives. Antibiotics are class of antimicrobials produced by microorganisms and other living systems capable of inhibiting dangerous bacteria. They can be bacteriostatic (slow down bacterial growth) or bactericidal (kill bacteria), broad-spectrum (effective against wide range of infections), narrow-spectrum (effective against few types of bacteria) or they can be used prophylactically. The choice of antibiotics depend on the kind of bacteria, severity of infection or other medical and physiological factors.