Common cold is not cured by antibiotics because it is:

Explanation

Common cold is caused by some 100 types of Rhinoviruses. It is one of the most common infectious diseases in humans. Antibiotics are substances that destroy or inhibit the growth of microorganisms, particularly disease-producing bacteria and fungi. Antibiotics are obtained from microorganisms(especially molds) or synthesized. Many antibiotics interfere with the pathogen protein synthesis. Some (e.g. Penicillin) prevent cross-linking of the glycan chains of peptidoglycan molecules in bacterial cell walls. Since the viruses do not possess cell walls and their own protein-synthesizing apparatus, antibiotics do not attack them.