Antibiotic was seeing wonder drugs when they appeared because antibiotic can treat every infection. As soon, it was observed that the treated bacteria can build resistance in contrast to them and the resistance can be intrinsic or acquired. The antibiotics are chemical compounds, which minimize the production of microorganism and ultimately kill microorganism. Natural fermentation or chemical synthesis may help in the production of these drugs. The antibiotics are the drugs, which are obtained from the compounds by different microbial flora. It is also noted that not every antibacterial compounds are antibiotics and obtained completely by chemical synthesize. Though moldy materials helped in healing the wounds and infections, but it was observed in late 19th century that this was due to the microbes. Fleming’s, Chain’s and Florey’s clinical observations, development studies made a new innovation in antibiotics in the twenty century.