Common cold is not cured by antibiotics because it is Caused by a virus. Caused by a Gram-positive bacterium. Not an infectious disease. Caused by a Gram-negative bacterium.

The common cold is a viral infection of the upper respiratory system, which includes the nose, throat, sinuses, eustachian tubes, trachea, larynx, and bronchial tubes. The most common groups include rhinoviruses and coronaviruses. Antibiotics are useless against a cold, and can only enhance bacterial resistance, if used carelessly.