Penicillin: Alexander Fleming discovered penicillin in 1928 when he observed that a mold, Penicillium notatum, inhibited the growth of bacteria in a petri dish, leading to the development of the first antibiotic. Follow FBJoin WhatsAppSUBSCRIBE YoutubeRelated Articles: Read: अलेक्जेंडर फ्लेमिंग