What are antibiotics ? Who discovered the first antibiotic ?

Answer: Antibiotics are chemical substances produced by microbes (fungi or bacteria) that kill or stop the growth of other harmful microbes, mainly bacteria. The first antibiotic, penicillin, was discovered by Alexander Fleming in 1928.

Fleming noticed that the mould Penicillium notatum growing on his culture plate had stopped the growth of bacteria around it. The substance responsible was named penicillin. Other examples of antibiotics are streptomycin and tetracycline. Antibiotics are used to treat bacterial diseases; they do not act on viruses.