Penicillin is arguably the most helpful medical discovery of the 20th century. It was discovered in 1928 as the active agent in a mould that can destroy and inhibit bacteria. Humans wind up with so many nasty bacterial infections like pneumonia that previously might just kill you, now were treatable! Not only did we discover (and eventually, mass produce) this particular drug, but it also kick started a whole new family of antibiotics for treating diseases.
Of course, we do eventually wind up some issues with antibiotic resistances of bacteria and some people wind up allergic, but at the time of discovery it must have truly seemed a panacea. Note that the Penicillium genus was known to be doing something against infections since the late 1880's, but the exact mechanism had not been identified.
That does seem really impressive. I am not really educated on this medicinal front, but should we at this point start looking for other antibiotics? Seeing that some Bacteria(I'm assuming) have become resistant to Penicillin, and more will eventually develop resistance to our Anti-Bacterial drugs.
I think there are lots of contenders to talk about in an opinionated discussion. The 20th century was pretty amazing for medical discoveries. I was actually not thinking of penicillin when I decided to post this discussion question. I was thinking about a specific discovery, though, when I asked. Call me totally childish, but I asked the question to see if anyone else thinks the same way as me. Gotta make this gig fun somehow, I guess! Anyway, so many contenders to have an opinion about. I'm not going to share mine because I want to see what people think and besides, it's just about opinions, not hardcore data or anything. I'm pretty sure we're alive today thanks to the many discoveries medical professionals made in the 20th century.