1. Antibiotics are secondary metabolites of therapeutic importance, produced in small amounts by certain microbes like bacteria, fungi and a few algae.
2. They inhibit growth of other microbial pathogens like fungi and bacteria.
3. Thus, they are antifungal and antibacterial in nature.
4. Antibiotics are used in treatment of deadly diseases like plague, whooping cough, diphtheria, leprosy, etc.
